Bulletin  of  the  Museum  of  Comparative  Zoology 

AT   HARVARD   COLLEGE. 

VOL.  LVII,  No.  6. 


FURTHER  STUDIES  ON  NORTH  AMERICAN  LITHOBIIDAE. 


BY  RALPH  V.  CHAMBERLIN. 


WITH  TWELVE  PLATE 


CAMBRIDGE,  MASS.,  U.S.A.: 

PRINTED  FORTHE  MUSEUM. 

JUNE,  1922. 


No.  6. —  Further  Studies  on  North  American  Lithobiidae. 
BY  RALPH  V.  CHAMBERLIN. 

THE  present  paper,  written  in  1914,  consists  of  revisions  of  new  or 
recently  described  genera  of  Lithobiidae  as  represented  in  America, 
north  of  Mexico. 

All  of  the  material  upon  which  this  paper  is  based  was  collected  by 
the  author,  unless  specifically  stated  to  the  contrary. 

The  key  will  aid  in  the  separation  of  the  genera. 

Key  to  the  Genera. 

a.     No  ocelli  present Typhlobius,  gen.  nov. 

aa.     Ocelli  present. 

b.     Prosternal  teeth  5+5  or  more. 

Posterior  angles  of  none  of  the  dorsal  plates  produced;  articles 

of  antennae  more  than  25 Sozibius  Chamberlin. 

bb.     Prosternal  teeth  normally  2+2,  or  occasionally  up  to  4+4. 
c.     Fourth  joint  in  anal  leg  of  male  with  a  lobe  at  proximal  end 

bearing  a  dense  brush  of  very  long  hairs. 
Posterior  angles  of  none  of  dorsal  plates  produced ;  articles  of 

antennae  about  24 Pampibius,   gen.   nov. 

cc.     Fourth  joint  of  anal  legs  of  male  not  thus  modified. 

d.     Articles  of  antennae  26  or  more.     (Posterior  angles  of 

ninth,   eleventh,   and   thirteenth  dorsal  plates,   or  of 

seventh,  or  of  sixth  and  seventh  in  addition,  produced). 

e.     Line  of  apices  of  prosternal  teeth  more  er  less  procurved, 

the  inner  tooth  of  each  pair  being  the  larger;    basal 

spines  of  gonopods  of  female  slender. 

Paitobius  Chamberlin. 

ee.  Line  of  apices  of  prosternal  teeth  recurved;  basal  spines 
of  gonopods  of  female  short  and  very  broad. 

Taiyubius   Chamberlin. 

dd.  Articles  of  antennae  normally  20,  rarely  as  many  as  24 
(but  when  so  none  of  dorsal  plates  with  posterior  angles 
produced) . 

e.  Poscerior  angles  of  ninth,  eleventh,  and  thirteenth  dorsal 
plates  strongly  produced;  neither  anal  nor  penult 
legs  of  male  with  any  special  process  or  lobe;  anal 
legs  with  two  or  three  claws. .  .  Sonibius  Chamberlin. 


260  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

ee.     Posterior  angles  of  none  of  dorsal  plates  produced  or, 

rarely,  those  of  eleventh  and  thirteenth,  or  of  ninth, 

eleventh,  and  thirteenth  weakly  produced,  but,  when 

so,  claw  of  anal  leg  single;  with  few  exceptions,  either 

anal  or  penult  legs  in  male  with  special  lobes  or  ridges, 

/.     Fifth  joint  of  anal  leg  of  male  always  bearing  on  dorsal 

surface  at  distal  end  a  conspicuous  crest. 

Nadabius  Chamberlin. 

ff.     Fifth  joint  of  anal  legs  of  male  with  no  such  crest. 

g.     Penult  legs  of  male  bearing  a  conspicuous  lobe  at 

distal  end  of  fifth  article,  but  anal  legs  without 

special  process Simobius,  gen.  nov. 

gg.  Penult  legs  of  male  bearing  no  such  lobe,  or  if  so 
the  anal  legs  also  strongly  modified;  the  third 
and  fourth  joints  of  the  latter  nearly  always 
longitudinally  ridged  and  produced  into  lobes, 
rarely  not  modified Pokabim  Chamberlin. 

SOZIBIUS  Chamberlin. 
Ann.  Ent.  soc.  Amer.,  1912,  6,  p.  152. 

Head  with  lateral  marginal  interruptions  distinct. 

Antennae  moderate  in  length  or  short;  composed  of  from  twenty- 
five  to  thirty-five  articles. 

Eye  composed  of  seriate  ocelli;  a  single  ocellus  usually  moderately 
enlarged,  but  sometimes  subequal  to  caudal  ocellus  of  upper  series. 

Prosternal  teeth  5+5  to  7+7;   spines  slender,  distally  bristle-like. 

Posterior  corners  of  ninth,  eleventh,  and  thirteenth  dorsal  plates 
'straight  or  somewhat  excised,  or  those  of  thirteenth,  or  of  eleventh 
and  thirteenth,  weakly  produced. 

Coxal  pores  circular  uni  seriate. 

Gonopods  of  male  uniarticulate. 

Claw  of  genital  forceps  of  female  large;  either  entire  or  with  one 
or  two  relatively  small  lateral  teeth  situated  well  proximad.  Spines 
2+2;  moderately  long  and  slender,  mostly  more  or  less  acuminate 
from  base.  First  article  of  forceps  not  excavated  proximally. 

Tarsi  of  all  legs  divided. 

In  the  anal  legs  of  the  male  the  fourth  joint  is  more  or  less  thickened, 
especially  distally  and  is  dorsally  longitudinally  furrowed  and  typically 
concave  or  saddle-shaped;  at  distal  end  more  or  less  elevated  dorsad 
(Plate  1,  fig.  1,  6). 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  261 

Last  one  or  two  pairs  of  coxae  laterally  armed.  Third  joint  of  all 
legs  caudad  of  first  to  sixth  pairs  with  three  dorsal  spines,  the  others 
with  two.  Fifth  joint  of  all  legs  between  third  and  eleventh  pairs  with 
two  dorsal  spines.  Dorsal  spines  of  anal  legs  1,0,3,  1,0;  ventral, 
1,  3,  3,  2;  the  claw  single.  Dorsal  spines  of  penult  legs,  1,  0,  3,  1,  1; 
ventral,  0,  1,  3,  3,  2;  claw  single.  Dorsal  spines  of  twelfth  legs, 
1,  0,  3,  1,  1  or  0,  0,  3,  1,  1;  ventral,  0,  0,  3,  3,  2.  Dorsal  spines  of 
first  legs  mostly  2,  1,  1,  occasionally  1,  1,  1  or  2,  2,  1;  ventral  2,  2,  1 
to  2,  3,  2. 

Length  8-14  mm. 

TYPE. —  S.  tuobukus  (Chamberlin). 

This  interesting  genus,  at  present  known  from  three  species,  has  a 
rather  restricted  distribution  (Fig.  1).  It  is  very  common  in  North 
Carolina,  Tennessee,  and  Virginia,  especially,  it  would  seem,  in  the 
mountainous  sections.  This  region  appears  to  be  the  center  of  dis- 
tribution. It  is  known  from  as  far  north  as  Philadelphia  and  as  far 
west  as  Arkansas. 

Key  to  Species  of  Sozibius. 

a.     Dorsal  spines  of  second  legs  0,  0,  3,  2,  1 ;    ventral  spines  of  first 
legs  in  adults  nearly  always  0,  0,  2,  3,  2;   claw  of  9  gonopods 

strictly  entire S.  providcns  (Bollman). 

aa.  Third  joint  of  first  three  to  six  pairs  of  legs  with  but  2  .dorsal 
spines,  the  formula  of  the  second  pair  being  0,  0,  2,  2,  1 ;  ven- 
tral spines  of  first  legs  0,  0,  2,  2,  1 ;  claw  of  9  gonopods  either 
bipartite  or  tripartite. 

b.     Last  pair  of  coxae  alone  laterally  armed;  first  five  or  six  pairs 
of  legs  with  third  joint  bearing  but  2  dorsal  spines. 

S.   pennsyhanicus,    sp.    nov. 

66.     Last  two  pairs  of  coxae  laterally  armed;  only  the  first  three  or 
four  pairs  of  legs  with  but  2  dorsal  spines  on  third  joint. 

S.  tuobukus   (Chamberlin). 

SOZIBIUS  TUOBUKUS  (Chamberlin). 
Plate  1,  fig.  6;  Plate  2,  fig.  1,  2. 

Lithobius  tuobukus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  36. 
Sozibius  tuobukus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  6,  p.  152. 

DESCRIPTION. —  Dorsum  light  brown  or  testaceous,  often  of  a  more 
or  less  orange  cast,  the  posterior  plates  commonly  in  some  degree 


262  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


FIG.  1.— Distribution  of  Sozibius. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  263 

darker.  Head  either  the  same  in  color  as  the  dorsum  or,  more  typi- 
cally, a  darker  brown  with  the  frontal  region  paler,  somewhat  orange 
or  ferruginous;  the  first  dorsal  plate  commonly  agreeing  in  color  with 
the  posterior  portion  of  head.  Antennae  light  yellowish  brown  proxi- 
mally,  yellow  distad.  Venter  pale  brown  or  brownish  yellow  with  the 
caudal  plates  darker.  Prosternum  and  prehensors  somewhat  orange- 
brown  to  very  dilute  chestnut.  Legs  pale  brownish  yellow,  the  caudal 
pairs  bright  yellow,  especially  distad. 

Body  moderately  narrowed  cephalad  to  the  first  dorsal  plate,  the 
widths  of  head  and  of  the  first,  third,  eighth,  tenth,  and  twelfth  plates 
being  to  each  other  as  64  :  58  :  60  :  69  :  72  :  67. 

Head  from  equal  in  length  and  breadth  to  wider  than  long  in  ratio 
20  :  19  or  less,  the  head  in  the  cf  appearing  to  be  wider  on  the  average 
than  in  the  9  •  Widest  just  caudad  of  eyes,  rather  conspicuously 
narrowed  cephalad;  caudal  margin  mesally  slightly  incurved.  Mar- 
ginal interruptions  very  slight,  sometimes  essentially  obsolete. 

Antennae  commonly  reaching  to  the  seventh  segment  but  some- 
times considerably  shorter  and  not  surpassing  the  fifth.  Articles 
twenty-five  to  thirty  of  intermediate  length;  the  ultimate  usually 
distinctly  shorter  than  the  two  preceding  taken  together,  distally 
pointed. 

Ocelli  from  nine  to  eighteen,  usually  in  four  series,  sometimes  in 
three:  e.g.,  1  +  5,  3,  2;  1  +  4,  5, 4;  1  +  3,  3,  2;  1  +  4,  5,  4,  2;  1  +  5, 
4,  4,  3;  1  +  5,  4,  3,  2;  1  +  2,  5,  5,  3;  1  +  6,  5,  4,  1.  Single  ocellus 
usually  only  a  little,  or  sometimes  not  at  all,  larger  than  the  most 
caudal  ocellus  of  the  dorsal  series,  the  corresponding  one  of  the  second 
series  also  often  large;  mostly  vertically  subelliptic,  but  sometimes 
circular  and  sometimes  angular.  The  seriate  ocelli  vary,  often  irregu- 
larly, in  an  unusual  degree  in  size,  form,  and  arrangement,  with  the 
series  frequently  very  irregular. 

Prosternum  1.6-1.7,  mostly  near  If,  times  wider  than  long.  Dis- 
tance between  the  chitinous  spots  1.87  +  2  times  the  width  at  level 
of  bottom  of  median  incision;  2.5  to  2.7  times  the  dental  line.  Teeth 
5  -f-  5  or  6  +  6,  rather  small,  uniform,  the  line  of  apices  forming  a 
distinctly  reentrant  angle.  Spine  slenderly  acuminate,  bristle-like, 
and  straight  or  nearly  so.  Incision  distinctly  u-shaped  or  with  the 
bottom  sometimes  somewhat  angular. 

First  dorsal  plate  with  the  sides  weakly  convex,  moderately  con- 
verging caudad  to  the  widely  rounded  caudal  corners;  caudal  margin 
mesally  incurved;  plate  1.6+  times  wider  than  long.  Caudal  margin 
of  the  ninth  plate  straight  all  the  way  across.  Eleventh  plate  with 


264  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

the  posterior  corners  showing  tendency  toward  weak  production,  while 
the  corners  of  the  thirteenth  plate  are  more  distinctly,  but  still  only 
slightly,  produced.  • 

Coxal  pores  circular:  3,  4,  4,  3;  3,  4,  5,  4;  4,  5,  5,  4;  4,  6,  6,  4; 
5,  6,  6,  5. 

Spines  of  first  legs,  JHJTO  or  OTO?  of  the  second,  otHrH  and 
tUH  to  orHri;  of  the  third,  J$Us  or,  occasionally,  0^fj;  of 
the  fourth,  MHHM  or  |ffH;  of  the  fourth  to  the  eleventh,  oHNH: 
of  the  twelfth,  TAlVi  of  the  thirteenth,  'fiUV  or  ^TO?  of 
the  penult,  fc  £  ii  £  2.  or  sometimes,  on  one  side,  fc  ?;  1 3.  i>  the  claw  single; 
of  the  anal,  l\ ";  1 3, 2  or  occasionally,  Htl-Bti.  or  the  spine  of  trochanter 
rarely  missing.  Last  two  pairs  of  coxae  normally  armed,  rarely  only 
the  anal. 

Anal  legs  of  the  male  with  the  third  article  thickened  into  a  rounded 
longitudinal  ridge  which  is  subdensely  clothed  with  long  bristles. 
Fourth  article  elevated  into  a  rounded  prominence  at  proximal  end, 
this  being  clothed  like  the  ridge  of  the  preceding  joint;  caudad  of  this 
elevation  the  joint  is  longitudinally  excavated  or  furrowed,  with  a 
ridge-like  elevation  on  each  side,  the  mesodorsal  one  of  which  increases 
in  height,  and  in  the  number  of  hairs  borne,  proximad,  while  the  ecto- 
dorsal  one  increases  in  similar  manner  distad  and  terminates  in  an 
elevation  at  distal  end  of  joint  which  is  often  conspicuous  and  which 
bears  the  dorsal  spine,  the  latter  frequently  projecting  directly  caudad 
(Plate  1,  fig.  6).  Penult  legs  more  slender  but  they  may  be  similarly 
though  more  weakly  modified. 

Gonopods  of  male  small  but  distinctly  exposed;  oblique. 

Claw  of  female  gonopods  large,  long,  well  curved,  and  very  acutely 
pointed;  bipartite,  the  main  lobe  bearing  the  second  near  the  middle 
of  its  length  on  the  outer  or  ventral  edge  as  a  very  small  denticle,  or 
tridentate,  a  denticle  appearing  at  nearly  the  same  level  on  the  outer 
edge  (Plate  2,  fig.  1).  Basal  spines  2  +  2;  the  outer  one  of  each 
pair  only  a  little  or  not  at  all  longer  than  the  inner;  in  ventral  view 
moderately  narrowing  from  base  to  near  middle  and  then  of  uniform 
width  to  the  beginning  of  the  acuminate  division  which  is  long  and 
acute;  outer  edge  often  denticulate  (Plate  2,  fig.  2). 

Length  9  to  13  mm. 

Early  pseudomaturus. — Body  yellow  or  brownish  yellow.  Head  and 
prosternum  darker,  orange.  Legs  yellow,  the  posterior  pairs  brightest. 

Antennae  consisting  of  twenty-six  articles  which  distad  of  the  third 
are  very  short  and  closely  united.  Ultimate  article  much  longer  than 
the  two  preceding  taken  together. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  265 

Ocelli  1  +  3,2.  Single  ocellus  and  first  two. of  the  upper  series 
subequal  in  size;  the  two  ocelli  of  the  ventral  series  much  smaller. 
Single  ocellus  not  distinctly  separated  or  otherwise  differentiated. 

Prosternum  of  same  form  and  structure  as  in  maturus.  Teeth  5  +  5, 
on  each  side  decreasing  mesad  and  the  most  mesal  one  considerably 
reduced. 

Coxal  pores  very  small:    2,3,3,3. 

Claw  of  female  gonopods  proportionately  shorter  than  in  the  maturus, 
with  the  lateral  tooth  or  teeth  occasionally  only  vaguely  indicated. 
Spines  2  +  2,  more  attenuated  distad  than  in  maturus  and  the  inner 
spine  proportionately  shorter. 

Spines  of  first  legs,  o  o'z'S'ii  of  tne  second  and  third,  oiriHH;  of  the 
fourth,  IHHrM  or  %$£$;  of  the  fifth,  (HHrH;  of  the  sixth  to  eighth, 
IHHHri;  °f  tne  remaining  pairs  as  in  the  maturus.  Last  two  pairs  of 
coxae  similarly  laterally  armed. 

Length  near  7.5  mm. 

Specimens  described,  collected  at  Johnson  City,  Tenn.,  in  August, 
1910,  are  nearly  between  usual  praematurus  and  pscudomaturus  stages. 

Immaturus. —  Coloration  as  in  preceding  form. 

Articles  of  antennae  twenty-four.  (Regenerating  antenna  on  one 
side  has  but  fifteen). 

Ocelli  1  +  2,  2;  1  +  2,  3.  First  ocellus  of  upper  series  larger  than 
the  single  ocellus.  All  contiguous. 

Prosternum  with  teeth  5  +  5,  the  most  mesal  on  each  side  being 
very  small.  Incision,  spines,  and  general  structure  as  in  the  older 
stages. 

Coxal  pores  very  small:  2,  3,  3,  2;  2,  3,  3,  3. 

In  the  gonopods  of  the  female  the  three  articles  are  present.  Third 
article  with  claw  indicated  as  a  small,  pale,  acute  point.  Second 
article  with  one  bristle,  the  first  with  three.  Spines  1  +  1,  minute, 
acute,  pale. 

Spines  of  first  legs,  JHfe-^H;  of  the  second,  |$TO  or  K&H;  of  the 
third,  o'oiil',  of  the  fourth  to  seventh,  ornH;  of  the  eighth  to  tenth, 
otfrH;  'of  the  twelfth,  JHHBri;  of  the  thirteenth,  HrlrH  (right  side) 
or  oi i', 1 2!  2  (left  side);  penult  and  anal  legs  missing  from  specimen 
described.  Last  three  pairs  of  coxae  dorsally  armed,  but  no  lateral 
spines  detected  on  any. 

Length  near  6.7  mm.     (Johnson  City,  Tenn.,  August,  1910). 

Agenitalis  I. —  Pale,  very  dilute  yellowish,  throughout. 

Antennae  very  short;  articles  twenty. 

Ocelli  1  +  2,  1,  also  in  one  case  1  +  3,  2  (South  Carolina).     First 


266  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

ocellus  of  upper  series  largest,  the  single  one  being  next  in  size,  while 
the  other  two  are  much  smaller. 

Prosternal  teeth  4  +  4. 

Coxal  pores  very  small:  1, 1,  1,  1. 

Anal  glands  fully  developed  and  very  distinct. 

Spines  of  the  first  legs,  <Hnnri;  of  the  second,  (Hnrfi;  of  the  third, 
IBrfrH  or  TOB;  of  the  fourth  to  seventh,  H$£i;  of  the  ninth, 
o|  °; i\  j;  i,  the  two  dorsal  spines  being  on  the  anterior  side;  of  the 
tenth,  o|  o!  I',  i,  i>  the  dorsal  spine  of  fourth  joint  being  caudal  and  that 
of  fifth  joint  anterior  in  position;  of  the  eleventh  to  thirteenth,  oloiiiiiii 
others  wanting.  None  of  the  coxae  armed  dorsally  or  laterally. 

Length  near  5  mm.     (Johnson  City,  Tenn.,  August,  1910). 

TYPE  LOCALITY. —  North  Carolina:    Hot  Springs. 

Also  taken  in  North  Carolina:  Linnville  Falls,  Brown's  Summit. 
South  Carolina:  Greenville.  Tennessee:  Johnson  City,  LTnaka 
Springs.  Virginia:  Chatham,  Lynchburg,  Natural  Bridge.  West 
Virginia:  White  Sulphur.  Kentucky:  Lexington. 

The  specimens  recorded  by  Bollman  from  Washington,  D.  C.,  as 
L.  providens  probably  belong  to  the  present  species. 

SOZIBIUS   PENNSYLVANICUS,   Sp.   nOV. 

Plate  1,  fig.  1-5. 

DESCRIPTION. —  From  light  brown  to  chestnut,  the  normal  color  in 
specimens  in  full  color,  the  species  being  darker  than  the  other  two 
known.  Head  and,  usually,  the  first  dorsal  plate  darker,  the  head 
having  a  dusky  or  black  area  or  spot  caudad  of  the  suture  in  front  of 
which  it  is  light  ferruginous  or  orange.  Antennae  brown  proximally, 
yellowish  distally.  Venter  but  little  paler  than  the  dorsum,  darkest 
caudally  as  usual.  Prosternum  and  prehensors  typically  dark  brown 
to  dilute  chestnut,  the  prehensors  paler  distad.  Legs  brownish  yellow 
or  brown,  the  posterior  pairs  more  brightly  colored,  commonly  bright 
yellow,  especially  distally  and  ventrally. 

Body  strongly  narrowed  cephalad,  the  widths  of  head  and  of  first, 
eighth,  tenth,  and  twelfth  plates  being  to  each  other  as  56  : 52  : 56  : 
64  :  66  :  60. 

Head  equal  in  length  and  breadth  strongly  narrowed  cephalad. 
Marginal  breaks  very  small  as  in  related  species. 

Antennae  short,  reaching  fifth  to  seventh  segments.  Articles 
nearly  always  twenty-seven  or  twenty-eight,  mostly  the  latter;  short 
and  very  short  and  usually  closely  compacted.  Ultimate  article  of 
moderate  length. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  267 

Ocelli  nine  to  fifteen,  usually  in  three  but  also  often  in  four  series: 
e.g.,  1  +  5,  4,  3;  1  +  5,  6,  4;  1  +  4,  4,  3;  1  +  3,  3,  2;  1  +  4,  3,  3,  1; 

1  +  5,  4,  3,  2.     Single  ocellus  somewhat  largest  or  equal  to  or  smaller 
than  first  of  upper  series  and  scarcely  differentiated.     Ocelli  varying 
much  in  relative  and  absolute  size  and  in  arrangement.     Organs  of 
Tomosvary  in  outline  usually  clearly  larger  than  any  ocellus  (Plate 
1,  fig.  2,  3). 

Prosternum  with  median  incision  small,  u-shaped.  Teeth  mostly 
5  +  5,  apically  rounded,  on  each  side  somewhat  decreasing  mesad. 
Spine  slender,  only  a  little  curved,  inserted  close  to  the  ectal  tooth  as 
usual.  1.73-1.76+  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2+  times  width  at  level  of  bottom  of  incision;  2.75  times 
the  dental  line. 

First  dorsal  plate  1.75+  or  more  times  wider  than  long;  widest 
cephalad  but  only  weakly  narrowed  caudad  to  the  rounded  corners. 
Posterior  corners  of  the  ninth,  eleventh,  and  thirteenth  dorsal  plates 
with  caudal  side  straight  or  slightly  rounded,  in  some  a  little  obliquely 
excised  on  one  side,  not  at  all  produced  or  rarely  showing  a  very  vague 
tendency  toward  production. 

Coxal  pores:  2,3,3,2;  3,3,3,3;  3,3,3,2;  2,3,3,3;  3,4,4,4. 

Spines  of  first  legs,  Jjtf^i;  of  the  second,  KUl;  of  the  third, 
cHHHH'-  of  tne  f°urtn  to  sixth,  oHHri  or  S  o  2  3"  2.  or  of  sixth  some- 
times fHHHH;  of  the  seventh  to  eleventh,'  S4f|;  of  the  twelfth, 
o; oil 3! 2?'  of  the  thirteenth,  0.1!  is!  2?  of  the  penult,  HrfrB;  of  the 
anal,  orHrH-  Only  the  last  pair  of  coxae  laterally  armed. 

Fourth  joint  of  the  anal  legs  in  the  male  moderately  thickened; 
the  dorsal  surface  bowed  in  concavely  between  the  ends  and  longi- 
tudinally shallowly  furrowed;  elevated  at  distal  end;  hairs  straight, 
sparse,  much  fewer  than  in  providens  and  tuobukus  (Plate  1,  fig.  1). 

Claw  of  female  gonopods  large;  only  moderately  curved;  subacute; 
always  with  a  distinct  small  lobe  or  tooth  on  the  outer  or  ventral 
edge  a  little  distad  of  middle  of  length  and  there  may  also  be  a  smaller 
denticle  on  the  dorsal  edge  farther  distad  (Plate  1,  fig.  4).  Spines 

2  +  2;   outer  one  of  each  pair  a  little  longer  than  the  mesal  one;  in 
ventral  view  both  spines  appear  distinctly  and  uniformly  acuminate 
from  base  to  apex  with  the  sides  appearing  smooth  or  the  ectal  edge 
of  inner  spine  showing  denticulations,   but   these  commonly   bent 
dorsad  and  not  always  evident  in  ventral  view  (Plate  1,  fig.  5). 

Length  8  to  10  mm.,  this  species  averaging  considerably  less  in  size 
than  either  of  the  other  two  species. 

Praematurus. —  (Male.)     Yellow  throughout.     Head  caudad  of  su- 


268  BULLETIN:  MUSEUM  OF  COMPAKATIVE  ZOOLOGY. 

ture  darker,  dusky  yellow;  frontal  region  dilute  orange.  Prosternum 
dusky  yellow,  prehensors  distally  a  brighter  yellow.  Legs  yellow. 

Antennae  composed  of  twenty  articles  which  are  short  and  closely 
united. 

Ocelli  1  +  3,  3;  1  +  3,  2.  Single  ocellus  smaller  than  the  first 
one  of  the  upper  series  which  is  much  larger  than  the  other  seriate  ocelli. 

Prosternum  with  incision,  spines,  and  general  structure  as  in 
maturus  stage.  Teeth  5  +  5. 

Coxal  pores  very  small:   2,  3,  3,  2. 

Spines  of  first  legs,  g^rri;  of  the  second,  IHKrH  or  o^fti;  of  the 
third,  gfrfi  to  IHHHB;  of  the  fourth,  JHHHK;  of  the  fifth  to  eleventh 
o-4rffi;  '  of  the  twelfth,  Hro;  of  the  thirteenth,  HHHH;  of  the 
penult,  fcUH;  of  the  anal,'  #£&. 

Anal  leg  of  male  with  the  fourth  joint  but  little  modified,  the  dorsal 
surface  being  slightly  bowed  and  a  little  elevated  distad. 

Length  7  mm. 

Pullus  II  (Larva  secundd). —  Body  and  legs  essentially  without 
pigment;  the  head,  prosternum,  and  antennae  with  a  very  dilute 
yellowish  tinge. 

Ocelli  1  +  2,  1.  First  ocellus  of  upper  series  largest,  the  single  one 
next,  the  other  two  being  much  smaller. 

Prosternum  with  median  incision  relatively  wide,  semicircular. 
Teeth  3  +  3. 

Eight  pairs  of  developed  legs  are  present,  the  slender  appressed  buds 
of  two  additional  pairs  appearing  caudad  of  these.  The  sixth,  seventh, 
and  eighth  pairs  of  legs  have  a  division  indicated  in  their  tarsi  while 
the  tarsi  of  the  more  anterior  pairs  appear  entire. 

Spines  of  first  to  seventh  pairs  of  legs,  <HHrH;  of  the  eiShth>  fHHriTT- 
Ventral  spine  of  tibia  relatively  long  and  stout,  much  exceeding  the 
others  in  size.  Ventral  spine  of  third  joint,  when  present,  small. 
Dorsal  spine  of  tibia  slender  and  almost  bristle-like.  Hairs  relatively 
long. 

Length  near  3.5  mm. 

TYPE.— M.  C.  Z.,  No.  94,  Pennsylvania:  Upsal,  October  20,  1912. 
Many  specimens. 

SOZIBIUS  PROVIDENS  (Bollman). 
Plate  2,  fig.  3-6. 

Lithobim  providens  Bollman,  Amer.  nat.,  1887,  21,  p.  81.  Proc.  U.  S.  N.  M., 
1887,  10,  p.  258.  Bull.  46,  U.  S.  N.  M.,  1893,  p.  19,  24,  79,  82,  85,  92, 
100,  110,  133. 


CHAMBERLIX:   NORTH   AMERICAN   LITHOBIIDAE.  269 

DESCRIPTION. —  Dorsum  light  brown  to  yellowish.  Head  darker, 
light  chestnut,  with  the  frontal  region  paler,  often  ferruginous.  An- 
tennae brown  or  brownish  yellow  proximally,  paler  distally.  Venter 
brown  to  yellow  of  paler  cast  than  dorsum;  the  posterior  plates  darker 
as  usual.  Prosternum  and  prehensors  light  chestnut  of  nearly  same 
shade  as  head.  Legs  like  corresponding  plates  of  venter  excepting 
that  the  caudal  pairs  may  be  lighter,  sometimes  being  bright  yellow, 
especially  ventrally  and  distally. 

Body  robust,  7  to  7.5  times  longer  than  width  of  tenth  plate.  Body 
considerably  narrowing  cephalad  to  the  first  dorsal  plate,  which  is 
decidedly  narrower  than  the  third,  the  widths  of  head  and  of  first, 
third,  eighth,  tenth,  and  twelfth  plates  to  each  other  as  65  :  58  : 62  : 
75  :  76  :  70. 

Head  precisely  equal  in  length  and  breadth,  or  very  nearly  so. 
Widest  just  caudad  of  eyes,  from  these  narrowing  gradually  and  but 
little  to  the  rounded  caudal  corners.  Posterior  margin  mesally 
incurved.  Lateral  marginal  breaks  small  but  usually  distinct. 

Antennae  usually  reaching  the  sixth  segment  but  sometimes  longer 
and  attaining  the  eighth.  Slender  distally.  Articles  twenty-eight 
to  thirty-five;  mostly  short;  rather  loosely  joined;  ultimate  long  and 
slender,  usually  a  little  longer  than  the  two  preceding  ones  taken 
together. 

Ocelli  nine  to  fifteen  in  four  series  or,  less  commonly,  in  three:  e.  g., 
1  +  3,3,3;  1  +  2,3,2,1;  1  +  3,3,3,2;  1  +  3,4,4,3;  1  +  4,4,4,2; 
1  +  4,  3,  3,  1,  and  1  +  4,  3,  3,  2,  the  two  last  seeming  to  be  the  com- 
monest arrangements.  Single  ocellus  commonly  largest  but  some- 
times equal  to  or  smaller  than  the  first  of  the  most  dorsal  series. 
Seriate  ocelli  varying  considerably  in  relative  and  absolute  size  in 
different  specimens  and  also  in  form,  being  sometimes  angular  or 
elongate  rather  than  circular. 

Prosternum  with  teeth  acute,  uniform,  moderate;  decreasing  some- 
what in  size  from  most  ectal  to  most  mesal  on  each  side;  line  of  apices 
on  each  side  a  little  convex,  as  a  whole  forming  a  reentrant  angle; 
teeth  in  number  5  +  5  to  7  +  7.  Median  incision  narrowly  u-shaped, 
often  narrower  at  mouth  than  at  bottom.  Spine  straight,  slenderly 
acuminate  and  bristle-like,  inserted  near  ectal  tooth.  If  to  1.7  times 
wider  than  long.  Distance  between  chitinous  spots  1.85-1.88  times 
width  at  level  of  bottom  of  mesal  incision;  2.75-288+  times  the 
dental  line  (Plate  2,  fig.  3). 

First  dorsal  plate  1.6+  times  wider  than  long.  Considerably 
narrowed  caudad,  with  the  sides  convex.  Ninth  plate  with  the 


270  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

caudal  margin  straight,  or  one  corner  may  be  obliquely  excised. 
Caudal  corners  of  eleventh  and  thirteenth  plates  slightly  produced, 
those  of  the  thirteenth  the  more  distinctly  so. 

Coxal  pores:  3,  4,  4,  3;  4,  4,  4,  3;  4,  5,  4,  3;  4,  4,  5,  4;  4,  5,  5,  4; 
4,  5,  5,  3;  5,  6,  6,  4;  etc. 

Spines  of  first  legs  usually,  HtlH  sometimes,  srorlti  inQ  specimens 
toward  pseudomaiurus  stage;  of  the  second  and  third,  o.' oils! 2?  of 
the  fourth  to  tenth,  fc^JJI;  of  the  eleventh,  jHHHB  or  $}fft>  of 
the  twelfth,  orBA  of  the  thirteenth,  JvHrH  claws  three;  of  the 
penult,  l',i,l',l',l;  of  the  anal,  o,  i,  I,  l\  I-  Last  two  pairs  of  coxae,  laterally 
armed. 

As  in  tuobukus,  the  fourth  joint  of  the  anal  legs  in  the  male  is  typi- 
cally conspicuously  thickened,  more  strongly  so  distad  than  proximad, 
and  is  elevated  dorsad  at  the  distal  end;  cephalad  of  this  rounded 
dorsal  elevation  the  joint  is  longitudinally  depressed  and  furrowed;  the 
bulge  or  ridge  along  mesodorsal  surface  mesad  of  the  furrow  clothed 
subdensely,  especially  toward  proximal  end,  with  very  long  bristles. 
Usually  the  fifth  joint  is  slender  but  is  somewhat  clavately  and  usually 
irregularly  enlarged  distad  and  may  in  fact  project  ventrad  in  a  con- 
spicuous lobe  at  the  distal  end.  Tibial  and  tarsal  joints  longitudinally 
sulcate  along  mesal  surface.  Penult  legs  slender,  writh  the  last  three 
or  four  joints  sulcate  longitudinally  on  caudal  (mesal)  side. 

Claw  of  female  gonopods  long,  not  much  curved,  scarcely  excavated 
on  inner  side;  comparatively  narrow  and  acutely  pointed;  strictly 
entire,  there  being  no  trace  of  lateral  teeth. 

Basal  spines  2  +  2;  long  and  rather  slender;  acuminate  from  base 
to  tip  which  may  be  very  narrowly  rounded;  in  ventral  view  the 
edges  are  either  smooth  or  one  or  more  denticles  may  appear  on  the 
ectal  edge  of  inner  spine,  or  occasionally  on  outer  one,  or  the  edges 
sometimes  finely  undulate;  if  the  spines  are  viewed  from  side,  how- 
ever, denticles  directed  dorsad  from  the  edges,  which  are  bent  or  partly 
rolled,  may  be  seen.  Extremes  of  variation  in  form  of  spines  are  shown 
(Plate  2,  fig.  5,  6). 

Length  11  to  14  mm.  A  male  14  mm.  long  has  antennae  7+  mm. 
long;  anal  legs  cir.  4.25  mm.  long;  and  tenth  plate  2  mm.  wide. 

Immaturus. —  Light  yellow.  Head  a  little  darker,  of  dilute  orange 
tinge.  Prosternum  and  prehensors  like  head.  Venter  yellow.  Legs 
light  yellow,  the  posterior  pairs  brightest. 

Antennae  composed  of  twenty-five  to  twenty-seven  articles  which 
are  mostly  short,  sometimes  with  two  shorter  ones  appearing  together 
at  intervals  and  being,  apparently,  the  result  of  more  recent  subdivision 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  271 

of  a  preceding  single  article.  Ultimate  article  long,  conically  acumi- 
nate, distally  rounded. 

Ocelli  1  +  2,  3.  The  first  ocellus  of  upper  series  imich  larger  than 
the  other  seriate  ocelli  and  as  large  as  or,  more  usually,  considerably 
larger  than  the  single  ocellus.  Organ  of  Tomosvary  relatively  large 
as  in  the  maturus. 

Prosternum  in  general  proportions  and  form  as  in  the  maturus. 
Median  incision  u-shaped,  with  sides  more  widely  divergent  than  in 
adult.  Teeth  4  +  4  or  5  +  5. 

Coxal  pores:  2,3,3,2;    3,3,3,3. 

The  three  articles  of  gonopod  of  female  are  present,  the  claw  on  the 
distal  one  being  also  represented  as  a  small,  acute,  chitinous  point. 
Basal  spines  1  +  1,  these  appearing  merely  as  acute  chitinous  points. 

Anal  glands  absent  or  obscurely  traceable  as  more  or  less  degenerated 
remnants. 

Spines  of  first  legs,  IHrrH;  of  the  second,  o4rrrl;  of  the  third, 
ffi£i  or  8£H*  of  the  fourth,  %%&$  or  fc^'to  jftttJ;  of  the 
fifth,  IHHrfi  to  oMHHH;  of  the  sixth,  [Hrm  or  HHHH;  of  the  seventh 

i      •'  V    'i  '  0.  0.  2.  2.  2         0.  0.  2.  2.  2         •  ,1        '  •'    ,1      0.  0.  2',  2.  2    5.  0.  2.  2.  2          0.  0.  2.  2,  2 

and  eighth,  0,0,1,1,2  °r  07072. 272  >  ol  the  ninth,  o,  071, 172,  o,  o.  i,  2, 2  or  070, 2, 272.' 
of  the  tenth,  ^IfH  to  [HHHH;  of  the  eleventh,  g'-JHH1!  or  JMH&1; 
of  the  twelfth,  JHHB^  or  ^IrH;  of  the  thirteenth,  b^^\  to  gj^|; 
penult,  o.'  i]  1;  I',  i  or  \\  °;  i;  2.  Q,  the  coxal  spine  minute.  Either  none  of  the 
coxae  laterally  armed  or  the  last  pair  with  a  very  small  lateral  spine. 

Length  6.5-7.5  mm.     (Russellville,  Tenn.,   August,   1910). 

Agenitalis  II. —  Light  yellow  throughout.  The  head,  prosternum, 
and  prehensors  a  little  darker,  of  an  orange  cast. 

Antennae  in  specimens  studied  with  twenty-two  or  twenty-three 
articles  which  are  short  or  very  short,  the  shortest  ones  occurring  in 
pairs  at  intervals  as  usual.  Ultimate  article  relatively  long,  clearly 
exceeding  the  two  preceding  together. 

Ocelli  1  +  2,  3;  1  +  2,  2;  1  +  2,  1.  The  most  caudal  eye  of 
dorsal  series  much  larger  than  any  other,  with  the  single  ocellus  next 
in  size.  All  ocelli  pale;  well  separated. 

Incision  of  prosternum  with  sides  divergent  as  in  preceding  stage. 
Teeth  4  +  4. 

Coxal  pores:   1,  2,  2,  2;    2,  2,  2,  2;  very  small. 

Gonopods  of  female  apparent  as  short,  biarticulate  buds. 

Anal  glands  absent  or  degenerate. 

Spines  of  first  legs,  jj^fi  or  fc^i*  of  the  second>  tttti;  °f  the 
third,  ^'-fH;  of  the  fourth  to  sixth,  ^;-H  or  o^rirH;  of  the  seventh, 
of  the  eighth  and  ninth,  OTTOTI;  of  the  tenth,  <HHHH;  of  the 


272  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


eleventh  and  twelfth,  fctttir  of  the  thirteenth,  g^fe0  or 

of  the  penult,  ftftti?;   of  the  anal,  °0\  °;  \',  i,  ",  the  trochanter  bearing  a 

bristle  distally.     None  of  the  coxae  armed. 

Length  5-6  mm.     (Russellville,  Tenn.,  August,  1910). 

TYPE    LOCALITY.  —  Indiana:     Bloomington. 

Also  taken  in  Indiana  at  La  Fayette,  Richmond,  Brookville,  Salem, 
New  Providence,  Wyandotte.  Tennessee:  Russellville,  Knoxville, 
Beaver  Creek,  Mossy  Creek.  Arkansas:  Little  Rock. 

TYPHLOBIUS,  gen.  nov. 

Head  with  lateral  marginal  interruptions  only  vaguely  indicated 
by  a  slight  obliquity  at  the  point  where  usually  developed. 

Antennae  short  to  moderate;  composed  of  twenty  to  twenty-eight 
articles. 

No  ocelli  present. 

Prosternal  teeth  2  +  2;  line  of  apices  recurved.  Spines  slender 
and  bristle-like. 

None  of  the  dorsal  plates  with  caudal  angles  produced. 

Coxal  pores  circular;   uniseriate. 

Gonopods  of  male  uniarticulate. 

Claw  of  female  gonopods  long  and  slender;  bipartite  (subentire) 
or  tripartite,  the  lateral  tooth  small  and  situated  well  proximad. 
Spines  2  +  2;  long  and  slender,  attenuated  from  base  distad. 

Tarsi  of  anterior  legs  slender;  distinctly  divided  and  the  distal 
segment  more  slender. 

Only  the  last  pair  of  coxae  laterally  armed.  Third  joint  of  first 
eight  to  eleven  pairs  of  legs  with  but  two  dorsal  spines,  or  the  most 
anterior  one  to  three  with  but  one.  Fifth  joint  of  all  legs  between 
third  and  thirteenth  with  two  dorsal  spines.  Dorsal  spines  of  anal 
legs  1,  0,  3,  1,  0;  ventral,  0,  1,  3,  2,  0  or  0,  1,  3,  2,  1  ;  claw  single,  long. 
Dorsal  spines  of  penult  legs,  1,  0,  3,  1,  1;  ventral,  0,  1,  3,  2,  1;  one 
accessory  claw  which  is  very  small  or  obsolete.  Dorsal  spines  of 
thirteenth  legs,  1,  0,  3,  1,  1  ;  ventral,  0,  1,  3,  3,  2  or  0,  0,  3,  3,  2.  Dorsal 
spines  of  twelfth  legs  0,  0,  3,  1,  2;  ventral  0,  0,  3,  3,  2.  Dorsal  spines 
of  first  legs  0,  0,  1,  1,  1  or  0,  0,  2,  2,  1  ;  ventral  0,  0,  2,  2,  1  or  0,  0,  2,  3,  1. 

Length  8  to  11  mm. 

TYPE.  —  T.  kebus,  sp.  nov. 

The  two  species  for  which  this  genus  is  established  are  small,  much 
alike  in  general  appearance,  and  characteristically  slender,  being  9.5 
or  10  times  longer  than  the  width  of  the  tenth  plate.  They  are  light 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  273 


FIG.  2. —  Distribution  of  Typhlobius. 


274  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

yellow  in  color  with  the  headjpale  orange.  Their  habits  are  not 
known;  but  the  absence  of  eyes  and  the  weak  pigmentation  would 
indicate  that  they  are  probably  more  strongly  lucifugous  than  usual. 


Key  to  Species  of  Typhlobius. 

a.     Articles  of  antennae  twenty;  trochanter  of  thirteenth  legs  with  a 
spine;  ventral  spines  of  anal  legs  0, 1,  3, 2, 1 .  .  T.  kebus,  sp.  nov. 
ia.     Articles  of  antennae  twenty-eight;   trochanter  of  thirteenth  legs 
unarmed;   ventral  spines  of  anal  legs  0,  1,  3,  2,  0. 

T.  coecus  (Bollman). 


TYPHLOBIUS  COECUS  (Bollman). 
Plate  3,  fig.  7;  Plate  4,  fig.  1,  2. 

Lithobius  coecus  Bollman,  Ann.  N.  Y.  acad.  sci.,  1888,  4,  p.  111.     Chamberlin, 
Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  36. 

DESCRIPTION. —  Dorsum  yellow  of  dilute  orange  cast.  Head  more 
distinctly  orange.  Antennae  light  distally,  proximally  approaching 
the  head  in  color.  Prosternum  like  head  but  a  shade  lighter.  Venter 
a  little  paler  than  dorsum,  the  caudal  plates  more  distinctly  orange 
than  the  others.  Legs  yellow,  the  caudal  pairs  most  densely  pig- 
mented. 

Body  slender,  usually  ten  times  longer  than  width  of  tenth  plate 
or  a  little  less.  Head  as  wide  as,  or  wider  than,  the  tenth  plate  and  the 
third  plate  narrower  than  the  first.  Widths  of  head  and  of  first, 
third,  eighth,  and  tenth  plates  in  a  female  measured  as  25  : 22  : 21  : 
23  :  24  :  23;  in  a  male  as  28.5  : 26  :  24  :  27  :  27  :  25. 

Head  cordate,  conspicuously  narrowed  from  caudal  edge  of  eyes 
cephalad.  Equal  in  length  and  breadth. 

Antennae  of  moderate  length;  strongly  attenuated  distad.  Articles 
mostly  twenty-eight  which  are  short  and  often  submoniliform. 
Bristles  long  and  subdense. 

Prosternum  1.6  times  wider  than  long.  Distance  between  chitinous 
spots  2.25  times  width  at  level  of  bottom  of  mesal  incision;  four  times 
length  of  the  dental  line.  Median  incision  v-shaped,  its  sides  from 
moderately  concave  to  nearly  straight.  Teeth  moderate  in  size,  the 
mesal  one  of  each  pair  a  little  larger  than  the  outer,  acute;  line  of 
apices  a  little  recurved.  Spine  inserted  at  base  of  outer  tooth,  small 
and  slender. 


CHAMBERLIN:    NORTH   AMERICAN    LITHOBIIDAE.  275 

First  dorsal  plate  about  1.65  times  wider  than  long.  Caudal 
margin  of  ninth,  eleventh,  and  thirteenth  plates  a  little  curved  for- 
wards at  ends,  the  corners  being  rounded. 

Coxal  pores  small,  the  most  proximal  ones  often  much  reduced: 
3,  3,  3,  3;  2,  3,  4,  3. 

Spines  of  first  legs,  rorti;  of  the  second,  o4r!4;  of  the  third, 
orlHB;  of  the  fourth  and'fifth.lHrHri2;  of  the  sixth  to  eighth,  JHH&I; 
of  the  ninth  to  eleventh,  Jo^H;  of  the  twelfth,  0.0!  a*,  a!  2?  of  the' thir- 
teenth, HrfrH;  of  tne  penult,  HrfrH;  of  the  anal,  HrHiTJ-  Last  Pair 
of  coxae  laterally  armed. 

Posterior  legs  of  male  short.  Penult  laterally  somewhat  com- 
pressed, distinctly  longitudinally  sulcate  on  the  caudal,  or  mesal,  side; 
fourth  joint  raised  along  dorsal  surface  into  a  ridge  which  is  elevated 
at  distal  end. 

Claw  of  female  gonopods  long  and  acute,  with  a  single  small  acute 
tooth  near  base  on  outer  or  ventral  edge.  Spines  2  +  2;  long,  the 
outer  larger  than  the  inner;  slender,  attenuated  from  base  to  tip. 

Length  8.5  to  11  mm. 

TYPE  LOCALITY. —  Tennessee:  Beaver  Creek.  Also  taken  in  North 
Carolina  at  Saluda. 

In  Bollman's  description  of  the  type  the  following  differences  may 
be  noted:  ventral  spines  of  anal  legs  0,  1,  3,  1,  0  and  of  the  penult 
0,  1,  3,  2,  0,  a  spine  probably  having  been  overlooked  on  fourth  joint 
of  the  anal  and  on  fifth  of  the  penult. 


TYPHLOBIUS  KEBUS,  sp.  nov. 
Plate  3,  fig.  5,  6. 

DESCRIPTION*. —  Dorsum  very  dilute  yellow,  the  pigment  a  little 
denser  on  the  first  one  and  the  several  most  caudal  plates.  Head 
light  orange-yellow.  Antennae  yellowish  proximally,  whitish  dis- 
tally.  Prosternum  like  head  but  a  little  paler.  Venter  similar  to 
dorsum,  the  caudal  plates,  as  usual,  more  densely  pigmented.  Legs 
with  faint  yellow  tinge. 

Body  very  nearly  9.5  times  longer  than  width  of  tenth  plate,  being 
very  slender  and  appearing  almost  parallel-sided,  with  the  head  wider 
than  any  dorsal  plate  and  the  first  plate  wider  than  the  third.  Widths 
of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to  each 
other  as  30  :  27  :  26  :  26  :  27  :  26. 

Head  nearly  equal  in  length  and  breadth,  being  slightly  wider. 


276  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Widest  a  little  in  front  of  marginal  breaks  and  strongly  narrowed 
cephalad.  Hairs  long,  very  sparse. 

Antennae  short,  attaining  the  fifth  segment.  Distal  portion  un- 
usually slender.  Articles  twenty,  moderately  short,  the  distal  ones 
slender  and  almost  strictly  cylindric.  Ultimate  article  very  long. 

Organ  of  Tomosvary  in  usual  position;  not  enlarged. 

Prosternum  with  median  incision  very  narrow  and  relatively  deep, 
its  sides  straight.  Teeth  moderately  large  and  well  chitinized;  inner 
tooth  of  each  pair  distinctly  larger  than  the  outer;  line  of  apices 
recurved;  ectal  side  of  outer  tooth  nearly  parallel  with  longitudinal 
axis  while  the  inner  edge  is  very  oblique,  the  reverse  being  true  of  the 
inner  tooth  (Plate  3,  fig.  5).  Spine  small  and  bristle-like,  straight. 
Prosternum  1.52  times  wider  than  long.  Distance  between  chitinous 
spots  2.4  times  width  at  level  of  bottom  of  mesal  incision;  3.8  times  as 
great  as  length  of  dental  line. 

First  dorsal  plate  1.8  times  wider  than  long;  sides  moderately 
convex  and  diverging  cephalad.  Minor  plates  with  caudal  corners 
subrectangular  or  simply  rounded.  Plates  very  sparsely  clothed  with 
short  hairs,  and  along  margins,  with  some  longer  hairs. 

Coxal  pores  very  small :  3,  4,  4,  3. 

Spines  of  first  legs,  o^Hl;  °f  tne  second,  °;  °;  1 1;  \,  or  oioilaj;  °f 
the  third  to  eleventh,  |^ff|;  of  the  twelfth,  fcft^l;  of  the  thirteenth, 
JrHrH;  °f  ^e  penult,  071!  3.'  I',  1>  one  accessory  claw  present,  this  being 
very  small  and  the  main  claw  long;  of  the  anal,  l\  °;  j|;  2;  i,  claw  long. 
Last  pair  of  coxae  laterally  armed. 

Claw  of  female  gonopods  of  moderate  size,  only  slightly  curved; 
distally  showing  two  blunt  teeth  or  lobes  separated  by  only  a  slight 
reentrant  angle  and  the  outer  larger  than  the  inner;  farther  toward 
base  is  a  small  tooth  on  the  ventral  or  outer  edge.  Basal  spines 
2  +  2. 

Length  9.25  mm. 

TYPE.— M.  C.  Z.,  No.  151.     California:   Santa  Barbara. 

PAMPIBIUS,  gen.  nov. 

Head  with  lateral  marginal  breaks  well  marked. 
Antennae  short;  in  type  species  composed  normally  of  twenty-four 
articles. 

Ocelli  present;  seriate;  single  ocellus  not  largest. 

Prosternal  teeth  2  +  2;    spines  slender  and  distally  bristle-like. 

Posterior  angles  of  none  of  the  dorsal  plates  at  all  produced. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  277 


FIG.  3. —  Distribution  of  Pampibius. 


278  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Coxal  pores  circular;   uniseriate. 

Gonopods  of  male  uniarticulate. 

Claw  of  female  gonopods  tripartite.  Basal  spines  2  +  2,  long  and 
slender.  First  article  not  excavated  proximally. 

Tarsi  of  anterior  legs  undivided. 

In  the  male  the  fourth  joint  is  conspicuously  crassate,  and  bears  a 
lobe  at  proximal  end  from  which  projects  a  brush  of  very  long  hairs. 

Last  two  pairs  of  coxae  laterally  armed.  Third  joint  of  first  ten 
pairs  of  legs  with  but  one  dorsal  spine,  that  of  only  last  two  pairs 
with  three,  that  of  about  first  seven  pairs  unarmed  ventrally.  Fifth 
joint  of  first  eleven  pairs  of  legs,  or  of  all  these  excepting  first  one  or 
two,  with  two  dorsal  spines.  Dorsal  spines  of  anal  legs  1,  0,  3,  1,  0; 
ventral  0,  1,  3,  2,  0;  claw  single.  Dorsal  spines  of  penult  legs 
1,  0,  3,  1,  1;  ventral,  0,  1,  3,  2,  1  or  0,  1,  3,  2,  0;  claw  single.  Dorsal 
spines  of  twelfth  legs,  0,  0,  2,  1,  1 ;  ventral  0,  0,  2,  3,  2.  Dorsal  spines 
of  first  legs  0,  0,  1,  2,  2  or  0,  0,  1,  1,  1;  ventral,  0,  0,  0,  1,  1. 

Length  of  type  species  6.5-7  mm. 

TYPE. —  P.  paitius  (Chamberlin). 

Only  one  species,  found  in  North  Carolina  and  Tennessee,  is  at 
present  known. 

PAMPIBIUS  PAITIUS  (Chamberlin). 

Plate  3,  fig.  1-4. 
Lithdbius  paitius  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  37,  pi.  3,  fig.  6. 

DESCRIPTION. —  Dorsum  pale  brown.  Head  and  posterior  seg- 
ments dark  orange.  Antennae  dull  yellow.  Venter  grey  or  greyish 
yellow.  Legs  pale,  greyish,  excepting  the  posterior  pairs  which  are 
bright  yellow,  with  the  brush  of  hairs  on  the  anal  legs  of  male  reddish 
proximally  and  yellow  distally. 

Body  a  little  narrowed  cephalad,  with  the  first  plate  narrower  than 
the  third.  Widths  of  head  and  of  first,  third,  eighth,  tenth,  and 
twelfth  plates  to  each  other  as  50  :  45  :  47  :  53  :  52  :  50. 

Head  subcordate;  caudal  margin  mesally  distinctly  incurved; 
moderately  narrowed  and  rounded  cephalad.  Marginal  breaks 
proportionately  large  and  distinct.  Wider  than  long  in  ratio  45  : 42. 

Antennae  short.  Composed  normally  of  twenty-four  articles 
which  are  short  between  the  second  and  the  ultimate,  and  decrease 
distad;  often  submonilif orm ;  ultimate  article  rather  slender,  moder- 
ately acuminate,  clearly  longer  than  the  two  preceding  together. 

Ocelli  six  to  nine  in  two,  or  sometimes  in  three,  series:  e.g.,  1  +  4,  1; 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  279 

1  +  4,2;  1  +  4,  3,1.  Single  ocellus  smaller  than  any  of  upper 
series,  or  equal  to  most  anterior.  Ocelli  of  lower  series  very  small 
(Plate  3,  fig.  2). 

Prosternum  with  median  incision  very  narrow  and  sides  nearly 
parallel  in  same.  Teeth  of  each  pair  widely  separated.  Spine  acutely 
acuminate,  attached  caudad  of  outer  edge  of  outer  tooth  (Plate  3, 
fig.  1);  1.7  times  wider  than  long.  Distance  between  chitinous  spots 
2.25-2.32  times  width  at  level  of  bottom  of  mesal  incision;  near  4.25 
times  the  dental  line. 

First  dorsal  plate  1.8+  times  wider  than  long;  sides  very  convex; 
strongly  narrowed  caudad,  with  posterior  corners  strongly  rounded. 
Caudal  corners  of  ninth  and  eleventh  dorsal  plates  rounded  or  shortly 
excised;  those  of  thirteenth  with  caudal  edge  straight. 

Coxal  pores  small:  1,3,3,2;  1,3,3,3;  1,3,4,3;  2,3,3,2;  2,3,3,3; 
2,3,4,3;  2,4,4,3;  etc. 

Spines  of  first  legs,  orHri  or  o,o,l',i,i'>  of  the  second,  ^oil'i;  of  the 
thM,  g;  °;  *;  \  \,  or  OTTO;  of  the  fourth  to  sixth,  o'.Kl.l',  of  the  seventh, 
oTorHri  or  t~orH;  °f  the  eighth  to  tenth,  o^iJJ;  of  the  eleventh, 
o. oil! 1 2?  °f  the  twelfth,  of 072! H!  °f  the  thirteenth,  orHrH;  °f  the 
penult,  o,  i!  3!  2!  i  or  oTirsrH'  claw  single;  of  the  anal,  oririrH,  claw  single. 
Last  two  pairs  of  coxae  laterally  armed. 

In  the  anal  legs  of  the  male  the  third  joint  is  clavately  thickened  and 
the  fourth  joint,  in  particular,  is  rather  strongly  crassate;  the  latter 
joint  has  at  its  proximal  end  on  the  dorsomesal  side  a  lobe  on  the 
posterior  surface  of  which  is  born  a  dense  brush  of  very  long  hairs 
which  extend  caudad  to  or  beyond  the  distal  end  of  the  joint  (Plate  3, 
fig.  3). 

Claw  of  female  gonopods  short;  parallel-sided;  well  curved;  tri- 
partite, with  the  lateral  lobes  equal  and  not  much  shorter  than  the 
median.  Spines  relatively  long  and  slender,  the  sides  a  little  incurv- 
ing at  middle,  apical  acuminate  portion  short  with  denticle  on  each 
side  at  base;  the  two  of  each  pair  of  nearly  same  length  (Plate  3,  fig.  4). 

Length  6.5-7  mm. 

TYPE  LOCALITY. —  Tennessee:   Unaka  Springs. 

Also  taken  in  North  Carolina  at  Catawba. 

PAITOBIUS  Chamberlin. 
Can.  ent.,  1912,  44,  p.  175. 

Head  with  distinct  marginal  lateral  interruptions. 
Antennae  short  but  often  reaching  seventh  or  eighth  segment; 
composed  of  from  twenty-six  to  thirty-four  articles. 


280  BULLETIN:  MUSEUM  OF  COMPAKATIVE  ZOOLOGY. 

Ocelli  from  seven  to  twenty  in  from  two  to  four  series;  single  ocellus 
enlarged. 

Prosternal  teeth  2  +  2;  line  of  apices  typically  more  or  less  pro- 
curved,  the  inner  tooth  of  each  pair  being  borne  farther  cephalad  than 
the  outer  (Plate  4,  fig.  3,  5).  Spines  distally  bristle-like,  median 
incision  v-shaped. 

Of  the  dorsal  plates  the  posterior  angles  of  ninth,  eleventh,  and 
thirteenth;  of  seventh,  ninth,  eleventh,  and  thirteenth;  of  sixth, 
seventh,  ninth,  eleventh  and  thirteenth,  or  sometimes  of  only  the 
eleventh  and  thirteenth,  are  produced. 

Coxal  pores  circular;   uniseriate. 

Gonopods  of  male  uniarticulate. 

Claws  of  female  gonopods  tripartite  or  rarely  only  bipartite;  basal 
spines  2  +  2,  slender,  acuminate  from  base.  First  article  not  exca- 
vated at  base. 

Tarsi  of  all  legs  divided. 

Posterior  legs  of  male  not  specially  modified.  Third  to  fifth  article 
of  anal  legs  more  or  less  distinctly  longitudinally  furrowed  above,  a 
little  more  crassate  in  male. 

Last  one  or  two  pairs  of  coxae  laterally  armed.  Third  joint  of 
first  six  to  eleven  pairs  of  legs  with  two  dorsal  spines,  or  occasionally 
the  first  one  to  three  pairs,  and  in  one  species  the  first  eleven  pairs, 
with  but  one  dorsal  spine  or  first  one  or  two  with  none;  others  with 
three.  Fifth  joint  of  all  legs  between  the  second  or  third  and  twelfth 
or  thirteenth  pairs  with  two  dorsal  spines.  Dorsal  spines  of  anal 
legs  1,  0,  3,  1,  0;  ventral  0,  1,  3,  2,  1  or  0,  1,  3,  2,  0,  rarely  0,  1,  3,  3,  1 ; 
claws  two  or  sometimes  but  one.  Dorsal  spines  of  penult  legs  1,  0,  3, 
1,  1,  less  commonly  1,  0,  3,  1,  0,  1,  0,  2,  1,  1  and  even  1,  0,  3,  2,  1; 
ventral  0,  1,  3,  3,  1  or  0,  1,  3,  3,  2;  claws  two  or  three.  Dorsal  spines 
of  twelfth  legs  1, 0,  3,  2,  2  or  0, 0,  3,  2,  2  to  0, 0,  3, 1,  2  and  0,  0,  2,  1,  2. 
Dorsal  spines  of  first  legs  0, 0,  0, 1, 1  to  0, 0,  2,  2, 1 ;  ventral  0, 0, 0, 0,  0 
to  0,  0,  1,  2,  1,  the  usual  formula. 

Length  of  species  6.5  to  12  mm. 

TYPE. —  P.  carolinae  (Chamberlin). 

The  species  of  this  genus,  even  in  the  case  of  the  adults,  in  most 
cases  show  a  purplish  pigment  which,  at  least  in  alcoholic  specimens, 
tinges  the  muscles  distinctly  and  modifies  the  color  of  the  entire  body, 
but  is  most  evident  in  the  anterior  ventral  plates,  antennae  and  head, 
and  the  caudal  pairs  of  legs.  The  anal  legs  are  always  dark  proxi- 
mally  with  the  tarsi,  or  the  tibiae  and  tarsi,  conspicuously  paler  and 
usually  yellow.  The  head  and  dorsum  are  smooth  and  shining,  never 
rugose. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE. 


281 


FIG.  4.—  Distribution  of  Paitobius. 


282  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

The  species  occur  chiefly  in  the  southeastern  states,  though  one  is 
known  from  Pennsylvania  and  another  from  New  York  City  (Figure  4). 

The  species  embraced  under  the  fourth  division  (aaaa)  in  the  fol- 
lowing key  may  be  regarded  as  constituting  a  separate  subgenus, 
Tunabius  (P.  zinus  Chamberlin,  TYPE)  differing  from  Paitobius  sens, 
str.,  including  all  the  remaining  species,  in  having  either  none  or  only 
the  eleventh  and  thirteenth  of  the  dorsal  plates  produced  and  in 
having  the  line  of  apices  of  prosternal  teeth  typically  straight  or 
slightly  recurved. 

Key  to  Species  of  Paitobius. 

a.     Posterior  angles  of  sixth,  seventh,  ninth,  eleventh,  and  thir- 
teenth dorsal  plates  produced, 

Ventral  spines  of  anal  legs  1,  3,  2,  1;  of  penult,  1,  3,  3,  2;  dorsal 

spines  of  thirteenth  legs  1,  0,  3,  2,  2. . .  P.  arienus  (Chamberlin). 

aa.    Posterior  angles  of  seventh,  ninth,  eleventh,  and  thirteenth  dorsal 

plates  produced. 

b.     Ventral  spines  of  anal  legs  1,  3,  3,  1;   of  the  penult  1,  3,  3,  1. 

P.juventus  (Bollman). 

bb.     Ventral  spines  of  anal  legs  1,  3,  2,  0;   of  the  penult,  1,  3,  2,  1. 

P.  carolinae  (Chamberlin). 
aaa.    Posterior  angles  of  ninth,   eleventh,   and  thirteenth   dorsal 

plates  produced. 
b.     Anal  leg  with  the  claw  single. 

Ventral  spines  of  anal  legs  1,  3,  2,  1;   of  the  penult,  1,  3,  3,  2; 
third  joint  of  all  legs  with  two  or  three  dorsal  spines. 

P.  naiwatus  (Chamberlin). 
bb.     Anal  leg  with  two  claws. 

c.     Ventral  spines  of  anal  legs  1,  3,  2,  1  and  of  penult  1,  3,  3,  2. 

d.     Dorsal  spines  of  thirteenth  legs  1,  0,  3,  2,  2;  dorsal  spines 

of  first  legs  2,  2,  1 ;    third  joint  of  first  seven  pairs  of 

legs  with  two  dorsal  spines.  .  .  .P.  tabius  (Chamberlin). 

dd.     Dorsal  spines  of  thirteenth  legs  0,  0,  3,  1,  1  or  1,  0,  3,  1,  1; 

dorsal  spines  of  first  legs  2,  1,  1;    third  joint  of  first 

eleven  or  twelve  pairs  of  legs  with  two  dorsal  spines. 

P.  adelus,  sp.  nov. 
cc.     Ventral  spines  of  anal  legs   1,3,2,0;   of  the  penult  also 

1,  3,  2,  0 P.  simitus  (Chamberlin). 

aaaa.     Posterior  angles  of  only  eleventh  and  thirteenth  or  of  none  of 
the  dorsal  plates  produced Tunabius,  subgen.  nov. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  283 

b.     Anal  leg  with  the  claw  single. 

c.     Ventral  spines  of  penult  legs  1,  3,  3,  1;    third  joint  of  first 
eleven  pairs  of  legs  with  2  dorsal  spines. 

P.  watsuitus  (Chamberlin). 

cc.  Ventral  spines  of  penult  legs  1,3,2,0;  third  joint  of  first 
eleven  pairs  of  legs  with  only  one  dorsal  spine. 

P.  atlantae,  sp.  nov. 

bb.     Anal  leg  with  two  claws.     (Ocelli  ten  or  more  in  three  series). 

c.     Dorsal  spines  of  penult  and  of  thirteenth  legs  1,  0,  2,  1,  1; 

ventral  spines  of  penult  legs  1,3,2,  1;    dorsal  spines  of 

twelfth  legs,  0,  0,  2,  1,  2 P.  cxccptus,  sp.  nov. 

cc.  Dorsal  spines  of  penult  and  of  thirteenth  legs  1,0,  3,  1,  1; 
ventral  spines  of  penult  legs,  1,3,3,  1;  dorsal  spines  of 
twelfth  legs  0,0,3,2,2  or  0,0,2,2,2. 

P.  zinus  (Chamberlin). 
The  key  does  not  include  P.  exiguus  (Meinert).     (Cf.  p.  302). 


PAITOBIUS  ARIENUS  (Chamberlin). 

Lithobius  arienus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  47. 

DESCRIPTION. —  Dorsum  brown,  darkened  caudad  and  sometimes, 
though  less,  cephalad.  Head  from  brown  and  but  little  darker  than 
the  dorsum,  with  a  transverse  band  along  the  frontal  suture  palest, 
to  a  darker,  dusky  or  dull  purplish,  brown.  Antennae  brown  suffused 
as  usual,  with  purplish,  distinctly  darkened  distad  to  the  ultimate 
article,  which  is  alone  paler.  Venter  pale  testaceous  to  brown,  becom- 
ing, as  usual,  darker  caudad,  and  the  last  several  segments  much  darker, 
of  a  somewhat  burnt  brown  tinge;  anterior  segments  showing  a  weak 
violaceous  or  purplish  tinge.  Prosternum  testaceous,  not  at  all,  or 
but  little,  darker  than  anterior  sternites,  or  appearing  in  some  dusky 
from  a  dull  purplish  pigment;  prehensors  paler  ectad  and  distad, 
excepting  the  claw.  Legs  testaceous,  with  the  tarsi  more  pigmented, 
or  they  may  be  suffused  with  the  purplish  pigment;  anal  legs  much 
darker,  deep  purplish  brown,  but  with  the  tarsi  lighter. 

Body  robust,  being  seven  times,  a  little  more  or  less  (cf ),  as  long  as 
width  of  the  tenth  dorsal  plate;  conspicuously  narrowed  from  the 
eighth  segment  cephalad  to  the  first.  Eighth  and  tenth  plates  of 
equal  width,  much  wider  than  the  head;  first  plate  clearly  narrower 
than  the  third.  Widths  of  head  and  of  first,  third,  eighth,  and  tenth 
plates  to  each  other  as  41  :  39  :  43  :  46  :  50  :  50. 


284  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Head  wider  than  long  in  about  ratio  41  :  38.  Subcordate,  widest 
at  marginal  breaks.  Caudal  margin  a  little  incurved  mesally.  A 
transverse  furrow  a  little  in  front  of  and  parallel  with  caudal  marginal 
rim,  its  ends  curving  forwards  to  lateral  breaks.  A  broad  furrow  on 
each  side  parallel  with  lateral  margin  as  far  forward  as  eye,  and  also 
a  furrow  each  side  of  middle  extending  cephalad  from  transverse 
furrow.  Smooth  and  shining,  punctae  few  and  indistinct. 

Antennae  reaching  the  seventh  segment.  Articles  thirty-two  to 
thirty-four,  of  moderate  length;  gradually  decreasing  in  size  from 
the  second  distad  to  the  ultimate. 

Ocelli  fourteen  to  twenty  in  four  or  five  series:  e.  g.,  1  +  4,  3,  3,  3, 1 ; 
1  +  4,  4,  3,  3,  2;  1  +  5,  5,  5,  3,  1.  Single  ocellus  much  the  largest, 
subvertically  oval,  with  the  narrower  end  ventrad.  Seriate  ocelli 
decreasing  in  size  ventrad  as  usual. 

Prosternum  1.5+  times  wider  than  long.  Teeth  proper  small  and 
dark,  but  elevated  on  the  usual  obtusely  angular  protrusions  of  the 
anterior  margin;  line  of  apices  distinctly  procurved. 

Sixth,  seventh,  ninth,  eleventh,  and  thirteenth  dorsal  plates  with 
posterior  angles  strongly  produced,  the  processes  of  the  sixth  being 
more  acute  than  those  of  the  seventh.  Major  plates  depressed  along 
lateral  and  caudal  borders.  On  elevated  portion  of  each  plate  in 
front  of  caudal  depressed  border  a  transverse  sulcus  continuous  at 
each  end  with  a  sublongitudinal  sulcus  running  a  little  ectad  of  cepha- 
lad; and  mesad  of  the  latter  are  two  other  sulci  the  inner  of  which 
diverges  from  its  mate  of  the  opposite  side  caudad. 

Sternites  with  a  median  longitudinal  furrow  most  distinct  on  ante- 
rior portion  of  plate  and  a  submarginal  furrow  as  usual  on  each  side. 
Two  transverse  furrows,  one  near  middle  and  one  a  little  cephalad  of 
caudal  margin. 

Coxal  pores  small  and  circular:  3,  4,  4,  3;  4,  5,  5,  3;  4,  5,  5,  4. 

Spines  of  first  legs,  £  £  o,  i.  i;  of  the  second  to  fourth,  IHHHH;  of  the 
fifth,  o  o"  i'  2  2  (or,  in  one  specimen  on  one  side  only,  "'  o  i'  2  1}  i  of  the 
sixth,  '££&!  or  8&H*  of  the  seventh,  jj^^l  or 'ifftHI;  of 
the  eighth,  % °; l't \ \  or  SiSUl;  of  the  ninth  and  tenth,  oHHH;  of  tne 
eleventh,  <HHfirl;  of  the  twelfth,  HHHri  or  o.  i  3.  \  1;  of  the 'thirteenth, 
oiii  a!  1:1;  of  the  penult,  ££££2;  claws'  two;  of' the  anal,  HrtH  claws 
two.  Last  two  pairs  of  coxae  laterally  armed. 

Male  with  anal  and  penult  legs,  as  usual,  moderately  crassate. 
Fourth  joint  of  anal  legs  thickened  and  dorsally  complanate,  with  a 
conspicuous  median  longitudinal  dorsal  furrow,  the  third  and  fifth 
articles  also  similarly  but  more  weakly  furrowed.  Corresponding 
articles  of  penult  legs  similarly  but  less  strongly  modified. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  285 

Gonopods  of  male  showing  a  pale,  conical,  and  apparently  glabrous 
process  extending  caudoectad  a  little  beyond  edge  of  sternite,  or 
sometimes  wholly  covered  by  the  latter. 

Length  of  types  10.5  to  11.5  mm.  A  specimen  10.5  mm.  long  has 
antennae  5  mm.  long;  anal  legs  (exclusive  of  coxae)  4.5  mm.  long; 
tenth  plate  1.6  mm.  wide. 

TYPE  LOCALITY. —  North  Carolina:    Hot  Springs,  August  6,  1910. 

Also  taken  in  South  Carolina  at  Taylors,  August  3,  1910. 

The  female  of  this  species  is  as  yet  unknown. 


PAITOBIUS  JUVENTUS  (Bollman). 

Lithobius  juventus  Bollman,  Proc.  U.  S.  N.  M.,  1887,  10,  p.  263,  1888,  11, 

p.  342,  1889,  11,  p.  410.     Chamberlin,  Can.  ent.,  1911,  43,  p.  99,  101. 
Paitobius  juventus  Chamberlin,  Can.  ent.,  1912,  44,  p.  175. 

DESCRIPTION.  —  Brown.  Head  darker.  Antennae  brown  proxi- 
mally,  fulvous  at  tips.  Venter  yellowish  to  brown.  Legs  like  adjoin- 
ing portion  of  venter;  posterior  legs  apparently  paler  distally.  Pre- 
hensors  paler  than  prosternum. 

Body  about  7.25  times  longer  than  width  of  tenth  plate.  "Width  of 
head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to  each  other 
as  50  :  47  :  49  :  59  :  61  :  56. 

Head  longer  than  wide  in  about  ratio  52  or  53  :  50.  Sides  strongly 
rounded  from  breaks  caudad  about  corners.  Posterior  portion  of 
head  with  two  longitudinal  sulci  diverging  cephalad. 

Antennae  short.     Articles,  in  type,  thirty-one  to  thirty-two;  short. 

Ocelli  1  +  53;  1  +  4,  3,  3.  Single  ocellus  moderate  in  size,  the 
most  caudal  of  uppermost  series  large. 

Prosternum  1.6  times  wider  than  long.  Distance  between  chitinous 
spots  2  times  width  at  level  of  bottom  of  median  incision;  3-3.25 
times  the  dental  line.  Line  of  apices  conspicuously  procurved  as  usual. 

Posterior  angles  of  seventh,  ninth,  eleventh,  and  thirteenth  dorsal 
plates  strongly  produced,  the  processes  of  the  last  three  being  espe- 
cially acute.  Posterior  margin  of  sixth  plate  straight. 

Coxal  pores  small,  circular;  in  types:   3,  4,  4,  3  and  4,  4,  4,  3. 

Spines  of  first  legs,  0717271;  of  ^e  second  and  third,  orHri;  of 


fourth  to  tenth,  o,  Mi;  of  the  eleventh  and  twelfth,  (HHBri;  of  the 
thirteenth,  °Q°i'l'£'£?',  '  of  the  penult,  HHbH  claws  two;  of  the  anal, 
o,  i,  I',  371  or  Hrlriri»  daws  two.  In  types,  which  are  in  poor  condition, 
no  lateral  spines  are  detectable  on  posterior  coxae  but  they  may  have 
been  lost. 


286  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Claw  of  female  gonopods  of  moderate  length,  rather  wide,  tripartite, 
the  lateral  lobes  small  and  acute,  the  outer  one  being  a  little  more 
proximal  in  position,  and  the  median  one  longest  and  much  broadest, 
acute.  Basal  spines  slender,  long  and  acutely  pointed,  subequal. 

Gonopods  of  male  small  and  wart-like,  almost  completely  concealed. 

Length  6.5-9  mm.  A  female  8  mm.  long  has  antennae  3  mm.  long, 
anal  legs  3.5—  mm.  long;  and  tenth  plate  1.1+  mm.  wide. 

TYPE  LOCALITY. —  Indiana:    Bloomington  (Bollman  coll.). 

Also  taken  in  Tennessee  at  Mossy  Creek  (C.  B.  Branner  coll.). 

The  description  above  is  based  upon  two  of  the  four  type  specimens 
from  Bloomington. 


PAITOBIUS  CAROLINAE  (Chamberlin). 
Plate  4,  fig.  5,  6. 

LithoUus  carolinae  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  47. 
Paitobius  carolinae  Chamberlin,  Can.  ent.,  1912,  44,  p.  175. 

DESCRIPTION. —  Dorsum  from  pale  yellowish  brown  to  dark  brown 
and  light  chestnut,  the  posterior  and  anterior  plates,  especially  the 
first  one,  darker  and  usually  tinged  with  red  or  purplish  red.  Head 
dull  purplish  red  to  reddish  chestnut,  paler  in  a  characteristic  band 
along  the  frontal  suture.  Antennae  dull  purplish  red  proximally 
but  pale  distad.  Prosternum  dull  brown  of  reddish  tinge ;  prehensors 
paler  ectad,  testaceous,  or  with  slight  tinge  of  ferruginous.  Venter 
from  dilute  brown  or  brownish  grey  to  darker  burnt  brown,  the 
more  caudal  plates  darker  and  having  the  characteristic  reddish  tinge, 
while  the  anterior  plates  are  often  suffused  with  purplish.  Legs 
nearly  like  corresponding  portions  of  venter,  becoming  darker  caudad, 
but  the  anal  and  penult  pairs  yellowish  distad. 

Body  conspicuously  narrowed  from  the  eighth  segment  cephalad 
as  usual.  Tenth  and  eighth  plates  nearly  equal  in  width,  clearly 
wider  than  the  head.  7.25  to  7.5  times  longer  than  width  of  tenth 
plate.  Widths  of  head  and  of  first,  third,  eighth,  and  tenth  plates  to 
each  other  as  32  :  29  :  30  :  37.5  :  37. 

Head  suborbicular;  almost  precisely  equal  in  length  and  breadth. 
Caudal  margin  straight.  Somewhat  depressed  transversely  in  front 
of  caudal  marginal  thickening  and  longitudinally  a  little  mesad  of  each 
lateral  margin  and  also  a  little  each  side  of  the  median  line,  the  depres- 
sions usually  wide  and  shallow.  Head  smooth  and  shining,  the  few 
punctae  present  being  very  fine.  Hairs  sparse,  in  part  long. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  287 

Antennae  short,  reaching  to  the  sixth  or  the  beginning  of  the  seventh 
segment.  Composed  mostly  of  from  thirty  to  thirty-five  articles 
which  distad  of  the  third  are  short  and  very  short,  the  shortest  ones 
often  alternating  singly  or  in  groups  with  longer  ones. 

Ocelli  from  eleven  to  sixteen  in  three  or,  less  commonly,  in  four 
series:  e.  g.,  1  +  5,  4,  3;  1  +  4,  3,  3;  1  +  5,  4,  3,  3.  Single  ocellus 
moderate  in  size,  a  little  obliquely  elliptic,  commonly  not  much  larger 
than  the  most  caudal  one  of  the  uppermost  series  which,  as  usual,  is 
elongate  longitudinally;  other  ocelli  decreasing  in  size  cephalad  and 
ventrad. 

Prosternum  1.5  times  wider  than  long  or  slightly  wider.  Teeth 
proper  small  but  borne  forwards  as  usual,  with  the  line  of  apices  dis- 
tinctly procurved.  Spines  in  usual  position,  bristle-like  distally. 

Posterior  angles  of  seventh,  ninth,  eleventh,  and  thirteenth  dorsal 
plates  produced,  the  processes  of  the  last  three  being  acute,  those  of 
the  seventh  more  obtuse.  Posterior  angles  of  sixth  plate  typically 
rounded  or  somewhat  excised.  All  major  plates  furrowed  transversely 
a  little  in  front  of  caudal  margin  and  longitudinally  within  each 
lateral  margin.  Elevated  portion  of  each  plate  with  a  longitudinal 
furrow  a  little  each  side  of  median  line  and  a  second  one  farther  ectad. 
Otherwise  the  plates  are  smooth  and  shining,  not  at  all  rugose.  Hairs 
very  short  and  sparse. 

Ventral  plates  longitudinally  depressed  or  furrowed  between  median 
line  and  each  lateral  margin,  the  furrows  most  distinct  caudad.  Ante- 
rior plates  transversely  depressed  between  bases  of  legs  and,  on  more 
caudal  plates,  a  second  transverse  furrow  appearing  as  usual,  in  front 
of  the  caudal  margin. 

Coxal  pores  circular,  the  most  proximal  on  each  coxa  often  very 
small:  3,4,4,3;  4,5,5,4;  4,5,4,3. 

Tarsi  of  all  legs  biarticulate,  but  those  of  anterior  pairs  with  division 
often  indistinct.  Anal  and  penult  legs  short,  considerably  inflated 
in  both  sexes,  but  somewhat  more  so  in  the  male.  In  both  the  femur 
is  widened  and  is  more  or  less  flattened  above  and  longitudinally  fur- 
rowed, the  prefemur  and  tibia  likewise  distinctly  longitudinally  fur- 
rowed. Penult  leg  similarly  furrowed,  but  less  crassate.  Thirteenth 
legs  with  third,  fourth,  and  fifth  joints  longitudinally  furrowed  above 
toward  each  side,  the  two  furrows  leaving  a  low  ridge-like  elevation 
between  them.  The  other  legs  similarly  furrowed  but  less  and  less 
distinctly  so  in  going  cephalad,  the  legs  being  more  or  less  distinctly 
laterally  compressed  and  somewhat  furrowed  longitudinally  along 
sides  of  joints. 


288  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


Spines  of  first  legs,  o^firi  or  (HHrH  rarely  oooii;  of  the  second, 
JlffH;  <>f  the  third  to  seventh,  j£J£i;  of  the  eighth,  'Km  or  {fttti; 
of  the  ninth,  g^ffi  to  H&tt  of  the  tenth  and  eleventh,  JtHf; 
of  the  twelfth,  g;  p.1  1  3.'  2  or,  rarely,  on  one  side,  sHBHH;  °f  tne  thirteenth, 
frit  £2?  of  the  penult,  o£JH  daws  two;  of  the  anal,  HHBre  (°r  in  a 
partly  regenerated  leg  observed  also  as  fc  °;  t  oi  o)>  claws  two.  Last 
pair  of  coxae  laterally  armec1 

Claw  of  female  gonopods  short  and  relatively  rather  broad,  thin,  and 
well  curved;  tripartite,  the  outermost,  or  most  ventral,  lobe  smallest 
and  sometimes  almost  obliterated,  the  median  considerably  longest, 
all  acute.  Basal  spines  moderately  long  and  slender,  the  inner  usu- 
ally somewhat  more  slender  than  the  outer;  both  gradually  narrowing 
distad  from  base  to  more  acuminate  apical  portion,  with  edges  of  latter 
portion  sometimes  minutely  denticulate. 

Length  8.5  to  10  mm.  A  female  9.5  mm.  long  has  antennae  3.8  mm. 
long;  anal  leg  3.2  mm.  long;  and  tenth  plate  1.3  mm.  wide. 

Praematurus.  —  Testaceous  or  pale  brown,  with  anterior  and  pos- 
terior plates  reddish.  Head  brownish  to  dull  purplish  red,  with  the 
transverse  pale  band  along  the  frontal  suture  as  in  the  adult.  An- 
tennae from  light  to  dark  dull  purplish  red,  pale  distad.  Prosternum 
and  prehensorial  feet  as  in  maiurus.  Venter  pale  testaceous,  the 
anterior  plates  suffused  with  light  purple,  the  caudal  plates  darkened 
as  usual.  Caudal  pairs  of  legs  dark  proximally  and  light,  yellowish, 
distad. 

Antennae  as  in  adult  or  nearly  so,  the  number  of  articles  complete, 
short,  and  very  short. 

Ocelli  1  +  4,  3,  2;  1  +  4,  3.  Single  ocellus  frequently  smaller 
than  most  caudal  one  of  upper  series,  which  is  large.  Ocelli  of  most 
ventral  row  small. 

Prosternum  as  in  adult. 

Posterior  angles  of  ninth,  eleventh,  and  thirteenth  dorsal  plates 
produced  acutely,  those  of  the  seventh  somewhat  more  weakly  pro- 
duced than  in  the  adult. 

Coxal  pores:  3,3,4,3;  3,4,4,3;  small,  the  most  proximal  especially  so. 

Claw  of  female  gonopods  shorter  and  less  curved  than  in  adult, 
pale  and  thin;  the  three  lobes  distinct  but  the  outermost  minute  and 
the  median  much  the  longest,  all  acute.  Spines  nearly  conical,  uni- 
formly narrowing  from  base  to  apex,  the  inner  spine  on  each  side  only 
about  one  fifth  shorter  than  the  outer,  the  two  spines  in  this  form 
appearing  to  develop  more  nearly  simultaneously  than  is  usual  in  most 
of  the  Lithobiidae.  Bristles  fewer  than  in  maiurus. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  289 

Spines  of  first  legs,  J  070!  i',  i^o  SHBro;  of  the  second  to  fourth,  {{;  o!  i,  I,  \ 
°r  oro.o'.  |i'>  °f  the  fifth,  {^{Hro  or  uioioiti;  of  the  sixth  and  seventh, 
oioioJri!  °f  the  eighth,  °;  u!  o!  2.'  i  or  u.'oloJJ;  of  the  ninth,  °; ";  %  j>; 1  or 
o.oiiip:  of  the  tenth,  SHnrH  or  uioiiill;  of  the  eleventh,  {HHHH  or 
<HHHH;  of  the  twelfth,  oiiliaj;  of  the  thirteenth,  o'iaV^a);  of  the 


penult,  orfrK;  of  the  anal, 

Length  7  to  7.5  mm.  A  specimei  .mm.  long  has  antennae  3.25 
mm.  long;  and  anal  legs  2.75  mm.  long. 

TYPE  LOCALITY. —  North  Carolina :  Asheville. 

Found  also  in  North  Carolina  at  Hot  Springs.  South  Carolina: 
Landrum.  Tennessee:  Russell ville. 

The  statement  (Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  47)  that  the  angles 
of  the  sixth  plate  are  produced  was  due  to  several  specimens  of  arienus 
(from  Taylors,  S.  C.)  having  been  included  in  the  description. 

.PAITOBIUS  NAIWATUS  (Chamberlin). 
Plate  4,  fig.  3,  4. 

Lithobius  naiwatus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  42. 
Paitobius  naiwatus  Chamberlin,  Can.  ent.,  1912,  44,  p.  175. 

DESCRIPTION. —  Dorsum  from  light  brown  to  dark  brown  and 
chestnut,  the  caudal  segments  darkest,  often  dark  brownish  purple. 
Head  from  dark  brown,  in  the  paler  specimens,  to  deep  purplish  brown 
or  purplish  chestnut  in  the  darker  ones ;  mostly  uniform,  but  the  frontal 
region  sometimes  a  little  lighter.  Antennae  concolorous  with  head 
proximally,  becoming  pale  distad,  the  end  portion  being  from  yellow 
to  rufous.  Venter  yellowish  brown  to  brown,  the  sternites  normally 
becoming  darker  from  the  anterior  ones  caudad,  the  last  four  or  five 
plates  being  especially  dark,  often  dull  reddish  brown.  Prosternum 
dark  brown,  usually  suffused  with  purplish;  prehensors  paler,  light 
ferruginous  or  rufous  distad.  Legs  yellow  to  brown,  the  last  two 
pairs  dark  purplish  brown  to  purplish  black  excepting  the  tarsi,  or 
tibiae  and  tarsi,  which  are  light. 

Body  robust,  being  relatively  very  wide;  conspicuously  narrowed 
cephalad;  typically  only  about  six  times  longer  than  width  of  the 
tenth  plate.  Widths  of  head  and  of  first,  third,  eighth,  and  tenth 
plates  to  each  other  as  87  :  80  :  77  :  95  :  100. 

Head  widest  between  eyes  and  marginal  breaks  as  usual.  Caudal 
margin  nearly  straight.  Smooth  and  shining,  not  at  all  roughened; 
a  few  minute  and  scattered  punctae.  Equal  in  length  and  breadth, 
or  slightly  wider. 


290  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Antennae  of  moderate  length,  normally  reaching  to  the  eighth 
segment,  or  sometimes  to  the  ninth.  Articles  beyond  the  second  of 
moderate  length  and  either  uniform  throughout  or  those  of  the  distal 
two  thirds  may  be  considerably  shorter  than  the  others.  Articles 
from  thirty-two  to  thirty-six.  Bristles  long,  not  very  dense. 

Ocelli  ten  to  sixteen  in  three  or  four  series:  e.  g.,  1  +  4,  3,  2; 
1  +  4,  4,  4;  1  +  4,  4,  3,  1;  1  +  4,  3,  3,  2;  1  +  4,  4,  4,  3.  Single 
ocellus  much  the  largest,  subvertically  elliptic,  often  paler  than  the 
others.  Series  regular,  the  ocelli  of  the  most  dorsal  one  often  sepa- 
rated by  a  small  space  from  each  other,  especially  so  those  toward  the 
caudal  end.  Organ  of  Tomosvary  in  outline  of  about  same  size  as  an 
average  sized  ocellus,  a  little  cephaloventrad  of  eye-patch. 

Prosternal  teeth  2  +  2  or  rarely  1  -+-  2 ;  those  of  each  pair  separated 
by  a  rather  wide  space;  margin  extended  beneath  each  tooth;  line  of 
apices  procurved.  1.6  times  wider  than  long. 

All  major  dorsal  plates  with  a  lateral  longitudinal  furrow  parallel 
with,  and  but  little  removed  from,  lateral  margin,  and  all  but  the  first 
with  a  sublongitudinal  furrow  each  side  of  the  middle  running  from 
anterior  end  obliquely  ectocaudad,  a  third  weaker  furrow  being  also 
more  or  less  evident  between  this  and  the  submarginal  one.  Not 
roughened.  Posterior  angles  of  ninth,  eleventh,  and  thirteenth  dorsal 
plates  produced. 

Ventral  plates,  excepting  the  first  one,  with  a  distinct  median  longi- 
tudinal sulcus  impressed  only  at  anterior  end  on  the  more  cephalic 
sternites  but  becoming  longer  and  more  distinct  on  the  caudal  ones. 
On  the  more  caudal  sternites  there  is  commonly  a  deep  impression 
in  the  form  of  an  inverted  v  which  is  most  acute  on  the  last  plates, 
the  mark  becoming  more  obtuse  and  less  and  less  distinct  in  going 
forwards. 

Coxal  pores  mostly  small,  pale  edged,  strictly  circular,  decreasing 
proximad  on  each  coxa  as  usual:  3,  4,  4,  3;  4,  4,  5,  4;  4,  5,  5,  4; 
5,  5,  5,  4;  5,  6,  5,  4;  etc. 

Spines  of  first  legs,  HHi;  of  the  second,  £tffi  or  g^f  $\;  of  the 
third,  [HHHB  or  JHHHK; '  of  the  fourth  and  fifth,'  g$f£i  or  sHHHH; 
of  the  sixth,  otorH;  of  the  seventh  to  the  tenth,  tSiU;  of  the 
eleventh,  jHHHri;  'of  the  twelfth,  oHHH  or  rrffl;  of 'the  thirteenth, 
HTO;  of  the  penult,  limi,  claws 'two;  'of 'the  anal,  HHHri»  the 
claw  single.  Only  the  last  pair  of  coxae  laterally  armed. 

Anal  and  penult  legs  in  male  short,  moderately  thickened,  with  the 
tarsi  more  or  less  abruptly  more  slender;  fourth  joint  clavately  thick- 
ened, dorsally  a  little  complanate  and  longitudinally  furrowed  above, 
the  corresponding  article  of  penult  legs  being  similarly  furrowed  but 


CHAMBERLIX:    XORTH    AMERICAN    LITHOBIIDAE.  291 

not  enlarged.  These  legs  are  similar  in  the  female  but  are  less  thick- 
ened and  have  the  furrows  weaker. 

Claw  of  female  gonopods  rather  slender  and  thin;  tripartite,  the 
lobes  acute,  with  the  median  longest.  Spines  of  each  pair  equal  in 
size  or  nearly  so ;  moderately  narrowing  from  base  to  distal  third  and 
then  more  abruptly  running  to  an  acute  point. 

Gonopods  of  male  broad  at  base;  distally  broadly  rounded  to  sub- 
conic. 

Length  from  9.5  to  13  mm. 

Pseudomaturus. —  Coloration  similar  to  that  of  adult  but  prevail- 
ingly somewhat  paler  throughout. 

Antennae  as  in  adult  but  articles  relatively  somewhat  shorter. 

Ocelli  1  -j~  443;   1  +  5,  4,  3;  larger  than  in  the  praematurus. 

Coxal  pores:  3,  4,  4,  3  to  4,  5,  5,  4,  small. 

Claw  of  female  gonopods  smaller  and  paler  than  in  adult,  especially 
in  specimens  toward  the  praematurus  stage,  with  lateral  lobes  relatively 
somewhat  smaller.  Basal  spines  as  in  adult,  or  the  inner  one  of  each 
pair  a  little  more  slender  and  shorter  relatively. 

Spining  of  legs  in  older  specimens  as  in  adult  while  youngest  ones 
may  have  formulae  as  follows: — fourth  and  fifth  pairs,  (HHHH  or 
Inrrirl;  seventh  and  eighth,  |Hrr-H  or  (Kr*-f1;  ninth,  ft-fror! ;  tenth 
and  eleventh,  JHHHH;  twelfth,  Kro;  thirteenth,  ViAT;  penult, 
ojil  1 3)2;  an&l  as  m  adult.  Last  pair  of  coxae  laterally  armed. 

Length  7.5  to  9  mm.     (Saluda,  N.  C.). 

Praematurus. —  Dorsum  brown.  Head  chestnut  suffused  with 
purple.  Antennae  dark  like  the  head  but  more  distinctly  purplish 
proximally ;  light  distally.  Prosternum  brown,  the  prehensors  lighter, 
especially  distad.  Venter  pale  greyish  yellow  to  yellowish  brown, 
more  brown  caudad.  Legs  pale,  the  two  last  pairs  darker  and  suffused 
with  purple  proximally,  yellowish  distally. 

Antennae  composed  of  thirty  to  thirty-one  articles  which  are  mostly 
of  moderate  length  as  in  adult,  but  shorter  ones  occur  at  intervals  in 
pairs. 

Ocelli  ten  to  thirteen  in  three  series:  e.  g.,  1  -\-  4,  3,  2;  1  +  5,  3,  3; 
1  +  5,  4,  3.  Of  the  seriate  ocelli  the  most  caudal  one  of  top  series 
is  relatively  large. 

Coxal  pores  very  small,  pale:  3,  4,  4,  3. 

Claw  of  female  gonopods  pale  throughout,  moderately  curved,  the 
three  lobes  present  but  the  median  one  much  exceeding  the  lateral 
ones,  which  appear  as  small  but  distinct  teeth.  Inner  spine  of  each 
pair  about  one  half  the  length  of  the  outer  one. 

Spines  of  first  legs,  OTTOW;  of  the  second,  o.  onrl;  of  the  third  and 


292  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

fourth,  IHHH&  of  the  fifth,  JHBHB;  of  the  sixth  to  eighth, 
of  the  ninth,  °; ";  %  \  \  or  IHHrH;  of  tne  tenth  and  eleventh,  „,„, ,,..,_ 
of  the  twelfth',  HjftJi;  of 'the  thirteenth,  orHrH;  of  the  penult, 
o]  i|  £  2,  o  or  o',  i',  s!  270 !  °f  the  anal,  0|  ii  3',  i,  o>  o!  i!  s!  2,  o>  °r  o!  i!  2!  i,  o-  No  lateral 
spine  as  yet  manifest  on  last  coxae. 

Length  near  7  mm.;  antennae  3.5  mm.;  anal  legs  cir.  2.5  mm. 
(Linville  Falls,  N.  C.). 

TYPE    LOCALITY. —  North  Carolina:    Saluda. 

Found  also  in  North  Carolina  at  Catawba  and  Linville  Falls. 
South  Carolina:  Landrum.  Georgia:  Tallulah  Falls. 

PAITOBIUS  TABIUS  (Chamberlin). 

Plate  5,  fig.  1. 
Lithobius  tabius  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  44. 

DESCRIPTION. —  Dorsum  dark  brown,  either  not  at  all  or  but 
slightly  darker  caudad.  Head  and  first  dorsal  plate  much  darker, 
chestnut  of  a  dull  purplish  red  tinge.  Antennae  concolorous  with 
head,  pale  distad.  Venter  light  brown  anteriorly,  becoming  darker 
and  darker  caudad;  in  some  the  entire  venter  is  suffused  with  pur- 
plish. Legs  pale  brown,  paler  ventrally  than  dorsally,  with  tarsi  yel- 
low; often  suffused  with  purplish;  legs  becoming  darker  caudad,  the 
two  last  pairs  especially  deep  in  color,  brown  of  a  dull  purplish  cast, 
with  the  tarsi  orange  or  light  ferruginous.  Prosternum  similar  in 
color  to  the  head  but  of  a  somewhat  paler  shade,  the  prehensors  lighter, 
dull  ferruginous.  The  characteristic  reddish  purple  tint  may  be  more 
or  less  evident  throughout  the  body. 

Body  considerably  and  uniformly  narrowing  from  the  tenth  plate 
cephalad,  with  the  head  and  the  tenth  plate  of  nearly  the  same  width. 
Body  typically  near  seven  times  as  long  as  the  width  of  the  tenth  plate. 
Widths  of  head  and  of  first,  third,  eighth,  and  tenth,  plates  to  each 
other  as  43  :  36  :  36  :  42  :  43. 

Head  suborbicular,  with  the  sides  conspicuously  and  rather  evenly 
•convex  and  the  caudal  margin  weakly  excurved.  Equal  in  length 
and  width  or  very  nearly  so,  widest  between  eyes  and  marginal  breaks. 
Head  usually  rather  broadly  and  shallowly  depressed  a  little  each  side 
of  the  median  line  from  near  caudal  margin  a  variable  distance  cepha- 
lad. Not  at  all  punctate  or  rugose,  smooth  and  shining. 

Antennae  short,  reaching  toward  end  of  seventh  segment  or,  occa- 
sionally, only  to  the  fifth.  Articles  between  the  second  and  ultimate 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  293 

• 

moderately  short,  not  much  varying  in  proportions;  in  number 
mostly  from  thirty  to  thirty-four. 

Ocelli  nearly  always  in  four  series,  occasionally  in  but  three;  from 
fourteen  to  twenty  in  number:  e.g.,  1  +  4,  4,  3,  3;  1  -4-  4,  4,  4,  3; 
1  +  4,  4,  5,  4;  1  +  4,  5,  4;  1  +  4,  5,  3.  Single  ocellus  well  separated, 
not  larger  than  most  caudal  one  of  most  dorsal  series.  Ocelli  of  caudal 
portion  of  most  dorsal  series  much  larger  than  the  others,  longitudi- 
nally more  or  less  elongate.  Ocelli  decreasing  markedly  in  size  from 
above  ventrad  and  in  each  series  from  caudal  end  cephalad. 

Prosternum  1.5  times  wider  than  long.  Distance  between  chitinous 
spots  2.25  times  greater  than  width  at  level  of  bottom  of  median 
incision;  3.2  times  the  dental  line.  Line  of  apices  procurved  in  the 
typical  manner.  Spine  distally  bristle-like. 

First  dorsal  plate  smooth  and  shining;  a  transverse  furrow  a  little 
in  front  of  caudal  margin  curving  cephalad  at  each  side  and  extending 
to  anterior  border.  Other  major  plates  marked  with  a  pair  of  distinct 
longitudinal  furrows  on  the  median  portion,  with,  between  them,  a  more 
shallow  median  furrow,  all  the  furrows  becoming  deeper  on  the  more 
caudal  plates;  a  transverse  furrow  a  little  ways  in  front  of  the  caudal 
margin,  this  laterally  bending  cephaloectad  and  entering  a  submarginal 
lateral  furrow  which  on  the  more  caudal  plates  is  wide  and  deep,  though 
only  weakly  developed  on  the  anterior  ones;  a  furrow  running  ob- 
liquely from  each  anterior  corner  to  meet  or  nearly  meet  the  longi- 
tudinal dorsal  furrow  of  the  corresponding  side. 

Ventral  plates  mostly  convexly  curving  from  ends  to  middle.  The 
usual  longitudinal  furrow  mesad  of  each  lateral  margin  mostly  weak; 
a  weak  median  longitudinal  furrow  often  evident,  this  most  distinct 
on  anterior  portion  of  plate;  the  usual  transverse  furrow  in  front  of 
caudal  border  more  or  less  distinct,  while  on  some  plates  a  second 
transverse  furrow  farther  cephalad  may  be  seen. 

Coxal  pores  circular  or  a  little  transversely  elongate,  of  moderate 
size.  Porigerous  area  more  or  less  depressed  and  marked  off  by 
lateral  elevated  rims:  4,  4,  4,  3;  4,  4,  4,  4;  4,  5,  5,  3. 

Spines  of  first  and  second  legs,  o;tirt  i!  °f  tne  third,  oiu'.iA  2?  of 
the  fourth  to  seventh,  oHHH;  of  tne  eighth,  otoHBHl  one  ventral  spine 
of  third  joint  very  small  or  occasionally  absent,  giving  formula  o'.u'.i'J'.2> 
of  ninth  to  eleventh,  oHHrl;  of  the  twelfth,  oHHri;  of  the  thirteenth, 
Hrffl;  of  the  penult,  VHrH  daws  two;  'of'  the  anal,  oTTO  or, 
in  one  specimen  on  one  side  only,  observed  as  07173727!'  claws  two. 
Last  two  pairs  of  coxae  laterally  armed. 

The  anal  and  penult  legs  are  short  in  both  male  and  female.     In  the 


294  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

• 

male  the  anal  legs  are  moderately  crassate,  the  thickening  being  most 
marked  in  the  fourth  joint  which  is  typically  wide  and  is  deeply, 
longitudinally  furrowed  along  the  dorsal  surface,  the  furrow  being 
deepest  and  widest  at  the  middle  of  its  length;  tibia  also  with  a  simi- 
lar, but  shallower,  longitudinal  furrow  as  also,  but  less  distinctly,  the 
prefemur;  tarsus  abruptly  more  slender  than  the  tibia.  Penult  legs 
somewhat  less  crassate;  similarly  furrowed.  The  immediately  pre- 
ceding legs  with  prefemur  and  femur  complanate  above  and  with 
a  dorsal  longitudinal  sulcus  toward  each  lateral  edge,  a  ridge-like 
elevation  between  the  two;  sulci  most  marked  on  femur;  more 
anterior  legs  similarly  but  less  distinctly  marked.  Most  of  the  legs 
somewhat  compressed,  the  joints  proximad  of  tarsus,  especially  tibia 
and  femur,  more  or  less  longitudinally  furrowed  along  each  lateral 
surface.  In  the  female  the  legs  are  similar  but  the  posterior  pairs  are 
less  inflated,  with  the  femur  not  conspicuously  broadened,  the  tarsi 
not  abruptly  more  slender,  and  the  sulci  less  distinct.  All  tarsi  biartic- 
ulate. 

Claw  of  female  gonopods  moderately  slender,  thin,  considerably 
curved;  bipartite,  the  outer  lobe  usually  obtusely  angular  and  much 
longer  than  the  more  acute  inner  one.  Basal  spines  subequal,  rather 
slender,  very  acutely  pointed.  The  statement  in  the  original  descrip- 
tion that  the  claw  is  tripartite  is  a  typographical  error. 

Length  9.5-10.5  mm.  A  male  10.5  mm.  long  has  antennae  cir.  5 
mm.  long  and  anal  legs  cir.  4  mm.  long,  with  tenth  plate  1.55  mm. 
wide. 

TYPE  LOCALITY. —  Tennessee:   Johnson  City,  August  9,  1910. 

PAITOBIUS  ADELUS,  sp.  nov. 
Plate  5,  fig.  3. 

DESCRIPTION. —  Dorsum  yellowish  brown  to  dark  brown.  Head 
distinctly  darker,  dusky  chestnut;  either  the  entire  frontal  region 
paler  or  paler  only  in  a  band  along  the  suture.  Antennae  like  head 
proximally,  paler  distad.  Venter  yellowish  to  light  brown.  Pro- 
sternum  darker,  somewhat  chestnut-brown,  the  prehensors  a  little 
lighter.  Legs  brownish;  the  caudal  pairs  as  usual,  darkest,  lighter 
mesally,  ventrally,  and  distally  than  dorsally  and  ectally. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  52  :  46  :  50  :  59  :  57  :  55. 

Head  nearly  equal  in  length  and  breadth  or  but  slightly  longer 
(53  :  52).  Much  narrowed  cephalad.  Caudal  margin  straight. 


CHAMBERLIX:    NORTH    AMERICAN    LITHOBIIDAE.  295 

Antennae  short,  typically  reaching  only  to  the  fifth  segment; 
strongly  attenuated  distad.  Articles  twenty-seven  to  thirty-one, 
twenty-nine  being  the  number  most  commonly  observed.  Articles 
distad  of  the  second  very  short  and  closely  united.  Ultimate  article 
considerably  longer  than  the  two  preceding  taken  together. 

Ocelli  mostly  twelve  or  thirteen  in  three,  or,  less  commonly,  in  four 
series:  c.  g.,  1  +  4,  4,  4;  1  +  4,  4,  3;  1  +  4,  3,  3,  2. 

Single  ocellus  usually  distinctly  largest,  or  sometimes  of  about  same 
size  as  the  most  caudal  one  of  dorsal  series;  others  decreasing  cepha- 
lad  and  ventrad. 

Prosternum  1.6  times  wider  than  long.  Distance  between  chiti- 
nous  spots  2.8—  times  greater  than  width  at  level  of  bottom  of  median 
incision;  3.5—  times  the  dental  line.  Teeth  acute,  moderate  in  size; 
line  of  apices  clearly  procurved.  Median  incision  narrowly  v-shaped, 
the  distance  between  apices  of  two  mesal  teeth  less  than  that  between 
apices  of  teeth  of  each  pair. 

First  dorsal  plate  widest  a  little  caudad  of  the  anterior  end,  its  sides 
convex  and  conspicuously  converging  to  the  rounded  caudal  corners; 
1.8  times  wider  than  long.  Posterior  angles  of  the  ninth,  eleventh, 
and  thirteenth  dorsal  plates  produced,  but  trie  processes  rather  short 
and  somewhat  obtuse. 

Coxal  pores  moderate  in  size,  distinct,  or  the  most  proximal  may  be 
very  small;  typically  3,  4,  4,  3. 

Spines  of  first  legs,  g$f£i  or  JJ-Jii;  of  the  second,  ffSi  °r 
of  the  third,  [Hrffi;  of  the  fourth,  JH!ff4  or  g&tH;  of  the  fifth, 
IHHHH;  of  the  sixth,  ££H!  or  ffiftl;  of  the  seventh,  JJ-Jti;  of 
the  eighth  to  tenth,  oHNri;  of  the  eleventh,  mHrl;  of  the  twelfth, 
of  the  thirteenth,  °^lrH  «  HSU  of  the  Penult> 
c'aws  tw°;  of  the  anal,  Q.  i',  I',  2,  i>  claws  two.  Last  two  pairs, 
or  occasionally  only  last  pair,  of  coxae  laterally  armed. 

Claw  of  female  gonopods  rather  short  and  wide,  tripartite,  with  all 
divisions  acute  and  the  median  considerably  broader  and  longer  than 
the  lateral.  Spines  long  and  slender,  the  outer  one  usually  only 
slightly  narrowed  from  base  to  the  acuminate  distal  portion,  which  is 
apically  narrowly  rounded  and  usually  has  a  denticle  on  each  side  at 
base;  inner  spine  more  uniformly  acuminate  from  base  to  apex,  with  a 
denticle  on  outer  side  near  middle. 

Length  6.5-8  mm. 

TYPE.— M.  C.  Z.  No.  128,  Pennsylvania:    Upsal. 

Also  taken  at  Philadelphia;  found  in  considerable  numbers  under 
fallen  leaves  and  limbs  in  chestnut  and  oak  groves.  Probably  a  close 
ally  of  P.  exiguus  (Meinert). 


296  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


PAITOBIUS  SIMITUS  (Chamberlin). 

LithoUus  simitus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  44. 
Paitobius  simitus  Chamberlin,  Can.  ent.,  1912,  44,  p.  175. 

DESCRIPTION. —  Dorsum  brown.  Head,  first  plate,  and  posterior 
plates  darker,  reddish  brown,  the  head  sometimes  paler  over  frontal 
region. 

Antennae  very  dark  proximally,  dull  purplish  red-brown,  much 
lighter  at  tips.  Prosternum  dark,  somewhat  dusky,  brown;  prehen- 
sors  paler,  testaceous  or  yellow,  especially  ectad  and  distad.  Anterior 
portion  of  venter  light  brown  and  suffused  with  purplish,  becoming 
darker  caudad,  the  last  plates  being  dark  brown.  Legs  mostly  very 
pale  brown  with  the  t  *rsi  clear  yellow,  the  anterior  pairs  suffused  with 
purplish,  anal  and  penult  pairs  dark  proximally  and  yellow  distally, 
especially  on  mesal  surface. 

Body  conspicuously  narrowing  from  the  eighth  plate  cephalad  to 
head,  the  first  plate  narrower  than  the  third,  and  the  eighth  and  tenth 
of  equal  width.  From  7.5  to  8  times  longer  than  width  of  tenth  plate. 
Widths  of  head  and  of  first,  third,  eighth,  and  tenth  plates  to  each 
other  as  27  :  24  :  26  :  29  :  29. 

Head  suborbicular,  widest  back  of  eyes  where  the  sides  are  weakly 
convex;  from  breaks  caudad  the  sides  are  convex  and  converge  con- 
siderably. Caudal  margin  straight  or  very  nearly  so.  Head  clearly 
longer  than  wide  (25  : 23).  Smooth  and  shining,  not  punctate. 

Antennae  very  short,  reaching  only  to  the  fifth  body  segment.  In 
types  composed  of  twenty-seven  to  thirty-three  articles  of  which  those 
distad  of  the  second  are  very  short  and  closely  compacted,  becoming 
relatively  a  little  longer  and  looser  distad. 

Ocelli  seven  or  eight  in  two  series:  1  +  4,  3;  1  +  3,  3.  Single 
ocellus  somewhat  paler,  subcircular,  not  at  all,  or  but  little,  enlarged. 
Other  ocelli  deeply  pigmented,  decreasing  markedly  cephalad,  the 
most  anterior  one  of  each  series  being  very  small. 

Prosternum  1.5  times  wider  than  long.  Inner  dental  process  on 
each  side  somewhat  larger  than  the  outer  as  usual,  and  line  of  apices 
more  or  less  procurved. 

Major  plates  depressed  within  each  lateral  margin  and  across  dor- 
sum  a  little  cephalad  of  caudal  margin,  in  the  latter  case  especially 
appearing  as  a  distinct  furrow.  Each  major  plate  excepting  the  first 
with  a  distinct  longitudinal  furrow  each  side  of  the  middle  line,  the 
two  diverging  a  little  caudad,  especially  near  the  ends,  where  they  often 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  297 

bend  ectad  in  the  caudal  transverse  depression  or  furrow;  between 
each  of  these  furrows  and  the  corresponding  submarginal  depression  is 
another  distinct  furrow  which  becomes  deeper  and  broader  on  the 
more  caudal  plates  as  do  also  the  others.  Posterior  angles  of  the 
ninth,  eleventh,  and  thirteenth  dorsal  plates  acutely  produced. 

First  sternite  with  a  median  longitudinal  depression.  Others 
mostly  clearly  longitudinally  depressed  mesad  of  each  lateral  margin. 
A  transverse  furrow  cephalad  of  caudal  margin  as  usual,  this  more 
pronounced  on  the  most  caudal  sternites. 

Coxal  pores  small,  decreasing  regularly  proximad  on  each  coxa; 
circular  and  pale  edged:  2,3,3,3;  3,3,3,3. 

Spines  of  first  legs,  5707070  or  0707071!  °f  the  second  and  third, 
of  the  fourth  to  sixth,  070717271;  of  the  seventh,  Q'  ^  \  \  \  or 
of  the  eighth,  oriHHj  °f  the  ninth,  QToTJTJrf;  of  the  tenth, 
of  the  eleventh,  0757-270;  °f  the  twelfth,  oioilaj?  °f  the  thir 
teenth,  07671°)'. \®>\  2  >  °f  the  penult,  oTiHHrfo  claws  two;  of  the  anal, 
57I7S/O»  claws  two.  Last  two  pairs  of  coxae  laterally  armed,-  though 
spines  of  penult  pair  may  be  minute  and  difficult  to  detect. 

Anal  and  penult  legs  in  female  short  and  moderately  enlarged. 
Fourth  article  in  anal  legs  somewhat  flattened  above  and  longitudi- 
nally furrowed,  the  third  and  fifth  articles  less  distinctly  sulcate. 

Claw  of  female  gonopods  of  moderate  size,  but  little  curved;  tri- 
partite but  the  most  ventral  lobe  much  the  smallest  and  sometimes 
scarcely  distinguishable,  median  much  the  largest,  all  acute.  Basal 
spines  subequal  in  length  but  the  outer  typically  somewhat  stouter 
than  the  inner,  narrowing  gradually  from  base  to  distal  fourth  or  fifth 
of  length  and  then  more  abruptly  narrowing  to  an  acute  point,  some- 
times showing  denticles  at  beginning  of  distal  portion.  Bristles  few. 

Length  of  type  7.7  mm.;  antennae  2.5  mm.  long;  anal  legs  near 
3  mm.  long;  tenth  plate  near  1  mm.  wide. 

TYPE  LOCALITY. —  Mississippi:   Grenada,  July  15,  1910. 


PAITOBIUS  WATSUITUS  (Chamberlin). 

Lithobius  watsuitus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  38  (ad  part. 
Atlanta  specimen). 

DESCRIPTION. —  Dorsum  light  brown.  Head  much  darker,  reddish 
brown,  or  chestnut.  Prosternum  colored  like  the  head  but  prehensors 
paler  distad.  Antennae  dark  brown,  paler  distad.  Anterior  plates 
of  venter  commonly  tinged  with  purplish.  Most  legs  light  yellowish 


298  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

brown  but  the  caudal  pairs  darker  brown,  excepting  the  tarsi  which 
are  light. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  47  :  41  :  43  :  53  :  52.5  :  50. 

Head  broadly  subcordate;  caudal  margin  straight  or  very  weakly 
convex;  moderately  narrowed  and  well  rounded  cephalad.  Equal 
in  length  and  breadth  or  slightly  longer  (48  : 47). 

Antennae  short.  Articles  thirty  to  thirty-two  which,  beyond  the 
third,  are  short  and  very  short  and  are  closely  united;  ultimate  much 
longer  than  the  two  preceding  taken  together. 

Ocelli  about  eight  in  two  series:  e.  g.,  1  +  4,  3. 

Prosternum  in  type  1.5  times  wider  than  long.  Distance  between 
chitinous  spots  2.53  times  width  at  level  of  bottom  of  mesal  incision; 
3.2  times  the  dental  line.  Mesal  tooth  on  each  side  more  elevated 
than  the  outer  and  the  line  of  apices  a  little  procurved.  Mesal  inci- 
sion v-shaped. 

First  dorsal  plate  with  sides  very  convex,  strongly  narrowed  caudad; 
1.8  times  wider  than  long.  Posterior  angles  of  eleventh  and  thir- 
teenth plates  distinctly,  though  not  strongly,  produced,  those  of  the 
thirteenth  the  more  so. 

Coxal  pores  very  small:  2,  3,  3,  3;  3,  3,  3,  3. 

Spines  of  first  legs,  J-j$Ji;  of  the  second,  <HHHrl  or  $$£#-,  of  the 
third,  [HHHH;  of  the  fourth,  H£K  (right  of  type)  or  jj#£H  (left  of 
type);  of  the  fifth  and  sixth,  IHHHri  (left  of  type)  or  oHuHH  (right  <>f 
type) ;  of  the  seventh,  g1 0021  (right)  or  "•  °0'  \  \  \  (left) ;  of  the  ninth, 
IHHHH;  of  the  eleventh,' IliH;  of  the  twelfth,  JHHrH;  of  the  thir- 
teenth, jHrlrH;  of  the  penult,  jHHrH  claws  two  or  witn  trace  °f  an 
anterior  accessory  claw  in  addition;  of  the  anal,  5717070'  c^aw  one- 

Anal  and  penult  legs  in  the  male  moderately  crassate,  especially 
so  the  fourth  joint  which  is  somewhat  flattened  dorso-ventrally  and  is 
longitudinally  weakly  furrowed  in  the  usual  way. 

Length  of  type  7.5  mm. 

TYPE  LOCALITY. —  Georgia:    Atlanta,  August,  1910. 

PAITOBIUS  ATLANTAE,  sp.  nov. 

DESCRIPTION. —  Dorsum  yellowish,  with  the  posterior  plates  light 
orange.  Head  orange.  Antennae  orange  proximally,  paler  distad. 
Prosternum  orange.  Venter  very  pale;  caudal  plates  light  orange. 
Legs  pale  like  the  venter,  the  posterior  pairs  correspondingly  more 
strongly  pigmented,  brown  of  an  orange  tinge. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  299 

Body  about  8-8.25  times  longer  than  width  of  tenth  plate.  Widths 
of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to  each 
other  as  36  :  34  :  36  :  43  :  43  :  40. 

Head  a  little  longer  than  wide  (37.5  : 36).  Strongly  narrowed 
cephalad  from  eyes.  Hairs  sparse,  both  long  and  short  intermixed. 

Antennae  short.  Articles  from  twenty-five  to  twenty-seven,  short 
and  very  short,  submoniliform.  Ultimate  article  long.  Hairs 
moderate,  not  very  dense. 

Ocelli  1  +  3,  the  first  or  most  caudal  ocellus  of  the  series  larger  than 
the  single  ocellus.  Pale. 

Prosternum  1.7  times  wider  than  long.  Distance  between  chitinous 
spots  2.25  times  greater  than  width  at  level  of  bottom  of  median 
incision;  four  times  as  great  as  the  dental  line.  Median  incision 
moderately  large,  strictly  v-shaped,  acute  at  bottom.  Teeth  small, 
acute,  equal  or  nearly  so;  line  of  apices  straight  or  even  slightly 
recurved.  Tubercle  of  spine  rather  prominent;  spine  more  slender 
than  teeth  but  less  bristle-like  than  usual,  but  slightly  longer  than  the 
teeth. 

First  dorsal  plate  with  sides  moderately  convex  and  moderately 
converging  caudad;  widest  a  little  in  front  of  middle;  1.8  times  wider 
than  long.  Posterior  angles  of  none  of  the  dorsal  plates  produced, 
those  of  the  ninth,  eleventh,  and  thirteenth  simply  rounded  or  a  little 
obliquely  excised. 

Coxal  pores  small,  circular:    2,  2,  2,  2;    2,  2,  3,  3;    2,  3,  3,  3. 

Spines  of  first  legs,  <nnrrl;  of  the  second,  <nrrf!  or  ?nrm;  of  the 
third  to  tenth,  (HnHrl  or  V[rBHi;  of  the  eleventh,  j&ift  of  the 
twelfth,  IHHro;  '  of'  the  thirteenth,  %&%&,  of  the  penult,  HHHd 
claw  one  (two) ;  of  the  anal,  HHHrl  claw  one-  Last  Pair  °f  coxae 
laterally  armed. 

Posterior  legs  of  male  moderately  and  uniformly  inflated.  Without 
any  special  lobes.  Fourth  and  fifth  joints,  more  particularly,  later- 
ally, longitudinally  sulcate. 

Claw  of  female  gonopods  moderate  in  length  and  curvature;  tri- 
partite, the  median  lobe  much  the  longest,  the  lateral  ones  subequal 
and  at  the  same  level,  all  acute.  Spines  2+2;  subequal;  slender; 
attenuated  from  base  distad,  the  sides  convex  and  more  strongly 
converging  immediately  proximad  of  tip;  sides  denticulate.  Inner 
side  of  first  article  nearly  straight. 

Length  6-7  mm.  A  female  6.75  mm.  long  has  antennae  2.2  mm. 
long  and  tenth  plate  .82  mm.  wide. 

TYPE.— M.  C.  Z.,  No.  130.     Georgia:   Atlanta. 


300  BULLETIN:  MUSEUM  OF  COMPAKATIVE  ZOOLOGY. 

PAITOBIUS  EXCEPTUS,  sp.  nov. 

DESCRIPTION. —  Dorsum  pale  brown,  the  first  few  and  the  last 
few  plates  considerably  darker.  Head  darker  brown  of  light  chestnut 
cast.  Antennae  brown  of  purplish  tinge  proximally,  pale  distally. 
Prosternum  dark  brown  with  prehensorial  feet  much  lighter,  testa- 
ceous. Venter  very  pale,  the  anterior  plates  strongly  suffused  with 
violaceous,  the  caudal  ones  darker,  brown.  Legs  like  the  contiguous 
plates  of  venter,  the  posterior  pairs  being  brown  excepting  distally, 
where  they  are  light  in  color. 

Body  of  type  about  8|  times  longer  than  width  of  tenth  plate. 
Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to 
each  other  as  45  :  39  :  40.5  :  48  :  48  : 44. 

Head  in  type  somewhat  longer  than  wide  (47  : 45).  Sides  rather 
strongly  convex  and  converging  from  lateral  breaks  caudad. 

Antennae  short  as  usual;  articles  in  types,  twenty-nine  (or,  on  one 
side  in  one  specimen,  twenty-six). 

Ocelli  eleven  or  twelve  in  three  or  four  series:  e.g.,  1  +  4,  3,  3; 
1  +  4,  4,  3;  1  +  4,  3,  3,  1.  Single  ocellus  largest.  Others  regular  in 
form  and  arrangement. 

Prosternum  in  type  1.48  times  wider  than  long.  Distance  between 
chitinous  spots  2.53  times  width  at  level  of  bottom  of  median  incision; 
2.9  times  dental  line.  Median  incision  strictly  v-shaped,  sides  straight. 
Teeth  acute,  of  moderate  size;  line  of  apices  straight.  Spines  slender. 
Lateral  slopes  straight,  beginning  at  spine  and  extending  directly 
ectocaudad,  the  anterior  portion  of  prosternum  being  correspond- 
ingly narrowed. 

First  dorsal  plate  with  sides  convex  and  converging  caudad  from  a 
little  in  front  of  middle;  in  type  1.77  times  wider  than  long.  Posterior 
angles  of  eleventh  and  thirteenth  dorsal  plates  a  little  produced. 

Coxal  pores  small  and  round  as  usual:  2,  2,  3,  2;  2,  3,  3,  2. 

Spines  of  first  legs,  IHrrfi  or  (Hrm;  of  the  second,  JHhHH;  of  the 
third  to  sixth,  o^HHHH;'  of  the  seventh,  IHHHH:  of  the  eighth,  [HHHH; 
of  the  ninth  to  eleventh,  Sola!  11;  of  the  twelfth,  o.VVa')!^;  of  the 
thirteenth,  of'Ag/.'i'g-;  of  th'e'p'enult,  orf~H  claws  two;  of  the  anal, 
o,'  i,  I]  l\  o,  claws  two,  with  dorsal  spine  of  coxa  sometimes  doubled. 

Anal  and  penult  legs  of  male  short;  but  little  and  uniformly  thick- 
ened. Third,  fourth,  and  fifth  articles  longitudinally  sulcate  dorsally, 
the  fourth  article  most  distinctly  so. 

Length  of  type  (cf)  7.5  mm. 

Female  unknown. 

TYPE.— M.  C.  Z.,  No.  129.     Alabama:   Jackson. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  301 

PAITOBIUS  ZINUS  (Chamberlin). 

Plate  5,  fig.  2. 
Lithobius  cantabrigensis  zinus  Chamberlin,  Ann.  Ent.  soc.  Amerv  1911,  4,  p.  41. 

DESCRIPTION. —  Testaceous  to  brown,  with  the  posterior  segments 
darker,  not  of  reddish  tinge,  the  anterior  plates  sometimes  tinged  with 
violaceous.  Head  dark  brown,  not  of  reddish  tinge.  Antennae 
purplish  brown,  pale  at  tips.  Prosternum  brown  of  a  lighter  shade 
than  head,  the  prehensors  paler.  Venter  dilute  testaceous,  the  caudal 
plates  darker,  burnt  brown.  Legs  nearly  like  corresponding  plates  of 
venter;  the  posterior  pairs  brown,  somewhat  paler  distally. 

Body  moderately  robust;  7.5  (Thomasville)  to  8  times  longer  than 
width  of  tenth  plate,  conspicuously  narrowed  from  eighth  segment 
cephalad  to  first  plate  which  is  much  narrower  than  the  head.  Widths 
of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to  each 
other  as  25  :  23  :  24  :  28  :  27  :  26. 

Head  well  rounded,  suborbicular,  from  about  equal  in  length  and 
breadth  to  a  little  longer  (51  : 49).  Caudal  margin  mesally  straight. 
Hairs  of  moderate  length,  sparse. 

Antennae  reaching  sixth  or  seventh,  or,  sometimes,  the  beginning  of 
,  the  eighth  segment.  Articles  twenty-eight  to  thirty-five  which  are 
mostly  very  short. 

Ocelli  eleven  to  sixteen  in  three  or  four  series:  e.g.,  1  +  4,  4,  3; 
1  +  3,  4,  3;  1  +  4,  4,  4;  1  +  4,  4,  4,  3.  Single  ocellus  moderate, 
only  a  little  largest.  Ocelli  of  dorsal  row  larger  than  others  of  series 
as  usual. 

Prosternum  1.47-1.48  times  wider  than  long  in  types.  Distance 
between  chitinous  spots  2.56-2.7  times  width  at  mesal  incision;  3.1- 
3.34  times  the  dental  line.  Median  incision  rather  narrowly  v-shaped, 
with  the  sides  nearly  straight.  Teeth  of  each  pair  well  separated, 
the  incision  semicircular,  the  sides  of  teeth  toward  each  other  slanting 
more  than  the  others;  inner  tooth  larger  than  the  outer  but  not  borne 
farther  forwards,  so  that  the  line  of  apices  is  a  little  recurved.  Sides 
slanting  directly  ectocaudad  from  spine,  and  straight  or  nearly  so. 

First  dorsal  plate  1.78-1.8  times  wider  than  long;  sides  strongly 
convex  anteriorly,  the  plate  being  widest  some  distance  caudad  of  the 
anterior  end;  sides  converging  strongly  caudad.  Caudal  margin  of 
ninth  plate  straight.  Posterior  angles  of  eleventh  and  thirteenth 
dorsal  plates  weakly  produced. 

Coxal  pores:  2,  3,  3,  2;  3,  4,  4,  3.  Small,  the  distal  one  on  each 
coxa  decidedly  larger  than  the  others  which  decrease  proximad. 


302  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Spines  of  first  legs,  o"rH;  of  the  second  and  third,  otorrtr;  of  the 
fourth,  Hm;  of  the  fifth,  yHHH  (Thomasville)  or  KfH  of  the 
sixth  and  seventh,  JfJH  of  the  eighth,  HHHrl  (Thomasville)  or 
cnriHrl;  of  the  ninth,  Hrfl  to  MHHrl  (Thomasville);  of  the  tenth, 
OTO  (Thomasville)  or  £tffl;  of  the  eleventh,  fcff-JI  (Thomas- 
ville)'or  [Hmrf;  of  the  twelfth,  IHHHri  to  JHHHrl;  of  the  thirteenth, 
OOT  (or'o^Hrl,  Thomasville  var.);  .of  the  penult,  HHrB  claws 
two,  or  with  minute  anterior  one  also  evident;  of  the  anal,  Q] "; I \ ", 
claws  two.  Last  one,  or  two  (Thomasville),  pairs  of  coxae  laterally 
armed. 

Claw  of  female  gonopods  of  moderate  size;  but  little  curved;  acute, 
with  a  small  acute  tooth  toward  base  on  ectal  side  and  a  similar  one 
on  mesal  side.  Spines  long  and  slender,  but  slightly  or  not  at  all 
converging  from  base  to  the  relatively  very  short  apical  portion,  which 
occupies  only  a  fourth  or  a  fifth  of  the  total  length.  Mesal  side  of 
first  article  straight  or  only  slightly  incurved. 

Length  7.5  to  10  mm.  A  female  7.75  mm.  long  has  antennae  3.75 
mm.  long;  anal  leg  3  mm.  long;  and  tenth  plate  .98  mm.  wide. 

TYPE  LOCALITY. —  North  Carolina:    Brown's  Summit. 

Taken  also  in  Virginia  at  Chatham,  Natural  Bridge,  Lynchburg, 
Balcony  Falls.  Alabama:  Anniston,  Thomasville  (variety).  Ten- 
nessee: Johnson  City.  Georgia:  Tallapoosa. 


PAITOBIUS  EXIGUUS  (Meinert). 

Lithobius  exiguus,  Meinert,  Vidensk.  meddel.  naturhist.  foren.  Kjoben,  1886, 
1884-1886,  p,  110.  (nee  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  4, 
p.  40;  Can.  ent.,  1911,  43,  p.  104). 

The  original  description  is  as  follows:  — 

Brunneus,  corpore  subtus  pedibusque  pallidioribus,  capite  fulvo;  sat  gracilis, 
sublaevis,  capite  suborbiculari,  fere  aeque  longo  ac  lato. 

Antennae  breviusculae,  31-articulatae  (articulis  brevissimis) . 

Oculi  ocellis  7,  in  series  2  digestis. 

Denies  prosternales  bini. 

Pori  coxales  2,3,3,2-3,4,4,3,  rotundati. 

[Laminae  dorsales  omnes  angulis  rectis.] 

Pedes  corporis  primi  paris  calcaribus  0, 0,  1 ;  pedes  anales  calcaribus 
1,  2,  1,  0- 1,  3,  2, 1,  [unguibus  binis],  armati.  [Pedes  penultimi  paris  unguibus 
binis  armati].  [Pedum  analium  coxae  calcare  singulo,  parvo  armatae]. 

Pedes  postici  breviusculi,  crassiusculi. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  303 

Genitalium  femineorum  unguis  sat  manifesto  trilobus,  aculeis  tenuibus, 
interioribus  quam  exterioribus  paulo  tenuioribus. 
Long.  6.5  mm.  (fern.) — 8  mm.  (mas.). 

LOCALITY. —  New  York  City.     (L.Lund). 


TAIYUBIUS  Chamberlin. 
Can.  ent.,  1912,  44,  p.  176. 

Head  with  distinct  lateral  marginal  interruptions. 

Antennae  short;    articles  twenty-eight  to  thirty-five. 

Ocelli  six  to  fourteen  in  three,  or  occasionally  but  two,  series; 
single  ocellus  much  largest. 

Prosternal  teeth  2  +  2  (or  very  rarely  3  +  3  in  individual  cases) ; 
line  of  apices  recurved  or,  at  most,  straight.  Spines  long,  distally 
bristle-like. 

Posterior  angles  of  the  ninth,  eleventh,  and  thirteenth  dorsal  plates 
produced. 

Coxal  pores  circular;  uniseriate. 

Gonopods  of  male  uniarticulate. 

Claw  of  female  gonopods  short;  tripartite.  First  article  with 
mesal  side  straight,  not  excavated  mesally.  Basal  spines  2  +  2,  or 
occasionally  3  +  3;  conspicuously  broad;  usually  widest  at  or  near 
beginning  of  acuminate  portion. 

Tarsi  of  all  legs  divided. 

Posterior  legs  of  male  without  special  modification. 

Either  none  or  the  last  one  or  two  pairs  of  coxae  laterally  armed. 
Third  joint  of  all  legs,  or  of  all  but  first  pair,  with  two  or  three  dorsal 
spines.  Fifth  joint  of  all  legs  between  second  to  fourth  and  twelfth 
pairs  with  two  dorsal  spines.  Dorsal  spines  of  anal  legs  1,  0,  3,  1,  0; 
ventral  0, 1,  3,  2,  1  to  0, 1,  3,  3, 0  and  0, 1,  3,  3, 1 ;  claws  two.  Dorsal 
spines  of  penult  legs  1,  0,  3,  1,  1;  ventral  0,  1,  3,  3,  1  or  0,  1,  3,  3,  2; 
claws  2  or  3.  Dorsal  spines  of  twelfth  legs  0,  0,  3,  1,  2  or  0,  0,  3,  2,  2; 
ventral,  0, 0, 2, 3, 2  to  0, 0, 3, 2, 2.  Dorsal  spines  of  first  legs  0, 0, 2, 2, 1 
or  rarely  fewer;  ventral  0,  0,  1,  2,  1  to  0,  0,  1,  3,  2. 

Length  9  to  15  mm. 

TYPE. —  T.  angelus  Chamberlin. 

This  genus  appears  to  be  very  close  to  Paitobius,  the  species  of  the 
two  genera  being  much  alike  in  habit,  coloration,  and  general  appear- 
ance. Taiyubius  is  to  be  distinguished  through  its  having  the  line  of 
apices  of  prosternal  teeth  recurved  and  through  the  broad  basal  spines 


304  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


FIG.  5. —  Distribution  of  Taiyubius. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  305 

of  the  gonopods  in  the  females,  these  standing  in  conspicuous  contrast 
to  the  slender  ones  uniformly  present  in  Paitobius.  Taiyubius  is  a 
prevailingly  western  genus,  all  the  species  occurring  west  of  the  Rockies 
excepting  harrielae  which  is  found  commonly  in  Colorado  but  also  in 
New  England  (Figure  5). 

Key  to  Species  of  Taiyubius. 

a.     Each  coxa  of  last  one  or  two  pairs  of  legs  armed  laterally  with  a 

spine. 

b.     Ventral  spines  of  penult  legs  1,  3,  3,  2;  of  the  anal,  1,  3,  3,  1; 

articles  of  antennae  mostly  34  or  35 .  T.  satanus  (Chamberlin). 

bb.     Ventral  spines  of  penult  legs  1,  3,  3,  1;   of  anal  legs  1,  3,  3,  0; 

articles  of  antennae  28-32 T.  purpureus  (Chamberlin) . 

aa.     None  of  the  posterior  coxae  laterally  armed. 

b.  Third  joint  of  about  first  nine  pairs  of  legs  with  but  two  dorsal 
spines;  ventral  spines  of  second  legs,  1,  3,  2;  articles  of  an- 
tennae mostly  26  to  29 T.  angelus  (Chamberlin). 

bb.  Third  joint  of  at  most  first  three  pairs  of  legs  with  two  dorsal 
spines;  others  with  3;  ventral  spines  of  second  legs  1,  2,  1; 
articles  of  antennae  mostly  35  to  39. 

T.  harrielae  (Chamberlin). 


TAIYUBIUS  ANGELUS. (Chamberlin). 
Plate  5,  fig.  4,  5. 

Lithobius  angelus  Chamberlin,  Proc.  Acad.  nat.  sci.  Phil.,  1903,  65,  p.  155. 
Taiyubius  angelus  Chamberlin,  Can.  ent,,  1912,  43,  p.  176. 

DESCRIPTION. —  Dorsum  light  brown  to  chestnut,  the  most  caudal 
plates  and  the  head  writh  the  first  plate  darker.  Head  often  paler  in 
front  of  the  suture.  Antennae  concolorous  with  the  head,  pale 
distad.  Venter  pale  testaceous  to  brown,  the  caudal  plates  con- 
siderably darker  and  more  reddish.  Prosternum  and  prehensora 
reddish  brown,  the  latter  paler  distad.  Legs  colored  like  correspond- 
ing plates  of  venter,  the  posterior  pairs  being  thus  darker,  brown  to 
chestnut,  uniform  or  sometimes  a  little  paler  distad.  The  body  is 
often  suffused  in  deeper  tissues  with  a  violaceous  pigment  which  is 
commonly  most  evident  in  venter. 

Body  considerably  attenuated  cephalad,  with  the  tenth  plate 
clearly  wider  than  the  eighth  and  than  the  head,  and  the  first  plate 


306  BULLETIN:  MUSEUM  or  COMPARATIVE  ZOOLOGY. 

narrower  than  the  third.  Body  (in  9  )  about  8  times  longer  than  the 
width  of  the  tenth  plate.  Width  of  head  and  of  first,  third,  eighth, 
and  tenth  plates  to  each  other  as  40  :  36  :  37  :  42  :  45. 

Head  suborbicular,  as  long  as  wide  or  nearly  so;  widest  at  marginal 
breaks  back  of  which  the  sides  are  convex  and  strongly  converge, 
rounding  about  corners  to  the  caudal  margin  which  is  nearly  straight. 
Smooth  and  shining  or  under  lens  appearing  very  finely  roughened  over 
the  middle  portion.  The  usual  median  longitudinal  sulcus  beginning 
at  a  short  transverse  mark  a  little  in  front  of  the  suture  and  extending 
cephalad.  A  wide,  shallow  longitudinal  furrow  each  side  of  the  middle 
running  forward  from  the  caudal  margining  sulcus.  In  some  there  is  a 
more  or  less  distinct  transverse  mark  on  each  side  a  little  ways  caudad 
of  the  frontal  suture.  Hairs  of  moderate  length,  sparse. 

Antennae  short  or  very  short,  reaching  only  to  the  fifth  or  sixth 
segment.  Articles  twenty-six  to  twenty-nine,  but  in  most  twenty- 
eight,  which,  beyond  the  first  few,  are  short  and  decrease  distad. 
Hairs  rather  long,  not  dense. 

Ocelli  mostly  ten  or  twelve  in  three  series:  e.g.,  1  +  4,  3,  2;  1  +  4, 
4,  3;  1  +  5,  3,  3.  Single  ocellus  much  largest,  sub  vertically  oval. 
Ocelli  distinct  and  series  regular;  the  ocelli  of  first  and  second  series 
largest,  decreasing  ventrad  and  cephalad. 

Prosternum  between  1.5  and  1.6  times  wider  than  long.  Distance 
between  chitinous  spots  4  times  greater  than  length  of  the  dental  line 
and  2.25  times  greater  than  width  at  level  of  bottom  of  mesal  incision. 
Teeth  2  +  2,  those  of  each  pair  close  together,  of  moderate  size,  the 
mesal  tooth  on  each  side  directed  somewhat  mesocephalad  and  its 
apex  caudad  of  the  line  tangent  to  apices  of  outer  teeth. 

First  dorsal  plate  smooth  and  shining  like  the  head,  under  the 
microscope  appearing  very  finely  roughened;  a  transverse  sulcus  in 
front  of  caudal  border  usually  continuous  at  each  end  with  a  longi- 
tudinal furrow  parallel  with  the  margin,  while  another  longitudinal 
furrow  may  be  more  or  less  distinguishable  each  side  of  the  median 
line.  Other  major  plates  also  with  a  transverse  caudal  furrow  and  a 
lateral  longitudinal  furrow  on  each  side  together  with  a  mostly  more 
sharply  impressed  longitudinal  furrow  farther  toward  the  middle,  this 
diverging  from  the  corresponding  one  of  the  other  side  caudad.  Plates 
very  finely  rugose,  becoming  more  distinctly  roughened  caudad. 

First  ventral  plate  with  a  median  basin-like  depression,  while  the 
others  show  more  or  less  distinctly  the  usual  three  longitudinal 
furrows,  these  becoming  more  distinct  in  going  caudad;  showing 
usually  also  two  wide  transverse  depressions  or  furrows,  one  anterior 


CHAMBERLIX:    NORTH   AMERICAN    LITHOBIIDAE.  307 

and  one,  more  distinct,  caudal,  with  sometimes  finer  lines  and  trans- 
verse rugae  in  the  interval  between  the  two. 

Coxal  pores  circular  or  slightly  transversely  elliptic:  4,  4,  4,  3; 
5,  5,  5,  4;  5,  5,  5,  5;  5,  5,  6,  5;  etc. 

Spines  of  first  legs,  JiHrlri  or  MriHH;  of  the  second,  orHHB;  of  the 
third,  InriHH;  of  the  fourth'to  ninth,' <HHHH;  of  the  tenth  and  eleventh, 
rarlrl;  'of 'the  twelfth,  JHHBrl;  of  the 'thirteenth,  J£Ji*  or  fctiii 
of  the  penult,  HrlrH»  claws  two;  of  the  anal,  l\ "; | \ ",  claws  two. 
None  of  the  coxae  laterally  armed. 

Anal  and  penult  legs  short,  moderately  thickened,  the  femur  and 
tibia  weakly  longitudinally  sulcate  above. 

Gonopods  of  female  of  moderate  size,  but  little  or  not  at  all  extend- 
ing beyond  caudal  end  of  the  last  dorsal  plate.  Claw  tripartite, 
the  lobes  acute,  with  the  median  one  but  little  longer  than  the  others. 
Mesal  edge  of  first  joint  nearly  straight.  Basal  spines  2  +  2,  con- 
spicuously flattened  above  base,  broad,  widening  distad  to  the  begin- 
ning of  the  distal  third  of  length  from  where  narrowing  to  a  point; 
edges  often  more  or  less  minutely  crenulate.  Inner  spine  as  usual, 
with  broad  surface  set  more  or  less  at  an  angle  with  that  of  the  outer 
one. 

Length  13  to  15  mm.  A  female  13  mm.  long  has  antennae  4.5  mm. 
long;  anal  legs  5  mm.  long;  width  of  tenth  plate  1.6  mm. 

TYPE.  LOCALITY. —  California:   Los  Angeles. 

Taken  also  in  California  at  Oroville  and  Santa  Barbara. 


TAIYUBIUS  SATAXUS  (Chamberlin). 

Lithobius  angelus  satanus  Chamberlin,  Can.  ent.,  1911,  43,  p.  380. 
Taiyubius  satanus  Chamberlin,  Can.  ent.,  1912,  44,  p.  176. 

DESCRIPTION. —  Dorsum  brown,  the  caudal  margins  of  the  anterior 
major  plates  darker.  Head  dark  brown,  paler  in  front  of  suture. 
Antennae  dark  brown  proximally,  becoming  pale  distad.  Prosternum 
dark  brown  with  the  prehensorial  feet  paler,  orange.  Venter  pale 
brown,  darker  caudad,  the  last  several  plates  being  distinctly  darkest; 
the  anterior  plates  suffused  with  violaceous.  Legs  similar  to  venter 
and  in  part  showing  a  violaceous  tint  as  in  most  species  of  Paitobius; 
posterior  pairs  darker  excepting  the  last  two  pairs  which  are  orange. 

Body  moderately  attenuated  cephalad;  eighth  and  tenth  plates 
nearly  same  in  width,  a  little  wider  than  head;  first  plate  a  little 
narrower  than  the  third.  Body  in  type  (cf )  not  quite  eight  times 


308  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

longer  than  width  of  tenth  dorsal  plate.  Widths  of  head  and  of  first, 
third,  eighth,  and  tenth  plates  to  each  other  as  34  :  31  :  32  :  36  :  36. 

Head  subrotund;  wider  than  long  (17  :  16).  Widest  near  marginal 
interruptions,  caudad  of  which  the  sides  strongly  converge.  Caudal 
margin  mesally  incurved.  Two  longitudinal  sulci  which,  beginning 
close  together  at  caudal  margining  sulcus,  diverge  cephalad  and  end 
abruptly  a  little  caudad  of  the  frontal  suture.  A  transverse  furrow  is 
indicated  a  little  in  front  of  and  parallel  with  the  suture  with  the  usual 
longitudinal  median  sulcus  extending  forward  from  it.  Finely  rough- 
ened. Hairs  of  moderate  length,  sparse. 

Antennae  short;  composed  of  about  thirty-four  or  thirty-five  com- 
pactly arranged  articles  of  which  the  second  is  largest  and  those  distad 
of  the  third  short  and  very  short.  Hairs  moderately  long  and  sub- 
sparse. 

Ocelli  six  to  nine  in  two  or  three  series:  c.  g.,  1  +  3,  2;  1  +  3,  3,  1 ; 
1  +  3,  3,  2. 

Prosternum  between  1.6  and  1.7  times  wider  than  long.  Distance 
between  chitinous  spots  three  times  the  length  of  dental  line  and  2+ 
times  greater  than  width  at  level  of  bottom  of  median  incision. 
Median  incision  semicircular.  Teeth  large,  acute. 

Excepting  the  first  one,  the  dorsal  plates  are  rather  distinctly  and 
considerably  rugose.  Each  major  plate  with  a  median  longitudinal 
sulcus  which  is  most  distinct  caudad;  on  each  side  a  longitudinal 
sulcus  diverges  from  the  median  one  caudad,  while  caudad  of  its  pos- 
terior end  a  shorter,  sharply  impressed  one  converges  toward  the 
corresponding  one  of  the  opposite  side;  farther  ectad  on  each  side  a 
longitudinal  sulcus  extends  parallel  with  margin  for  entire  length  of 
plate. 

Ventral  plates  with  the  usual  three  longitudinal  sulci  of  which  the 
median  one  is  usually  continuous  entirely  across  the  plate  and  is  the 
most  distinct,  especially  caudad.  Anterior  plates  usually  trans- 
versely broadly  depressed. 

Coxal  pores  small,  circular:  3,  3,  3,  2;  3,  3,  3,  3. 

Spines  of  first  legs,  Vu^ofiV'  of  the  second,  °;  °;  |  l't  I  or  070717171;  of  the 
third*  0707271715  of  the  fourth,  ";  £  \  \  \  or  070727!  5  of  the  fifth  to  ninth, 
5767|7||;  °f  the  tenth  and  eleventh,'  g;  g;  \  \  \  or  ret!!;  of  the  twelfth, 
o',o'.3.3.'2>  the  anterior  dorsal  spine  of  the  last  two  articles  minute;  of 
the  thirteenth,  %  °'  3,  \  \  (left)  or  orf!,'  2  fright) ;  of  the  penult,  o."  \,  3.'  I',  I, 
claws  three;  of  the  anal, »; ";  j|;  3; ",  claws  two.  Last  two  pairs  of  coxae 
laterally  armed. 

Posterior   legs  slender,   of  moderate  length.     In  both  anal   and 


CHAMBERLIX:    NORTH   AMERICAN    LITHOBIIDAE.  309 

penult  pairs  the  prefemur,  femur,  and  tibia  are  longitudinally  weakly 
furrowed  above. 

Gonopods  of  c"  clearly  extended;   narrow,  distally  rounded;   pale. 

Length  near  10  mm.  In  the  male  type,  which  is  10  mm.  long,  the 
antennae  are  3.8  mm.  long,  the  anal  legs  4.4  mm.  long,  and  the  tenth 
plate  1.25  mm.  wide 

Praematurus. —  Coloration  as  in  adult. 

Antennae  very  short.  Articles  twenty-eight  (left)  —  thirty-four 
(right),  the  two  antennae  differing  in  length  correspondingly. 

Ocelli  1  +  3,  2.  Single  ocellus  largest,  the  most  caudal  one  of 
upper  series  next;  ocelli  of  lower  row  smallest. 

Prosternal  teeth  3  +  3,  a  small  extra  one  being  present  at  edge  of 
incision  on  each  side,  the  other  two  of  usual  proportions. 

Coxal  pores  small:  3,  3,  3,  2. 

Spines  of  first  legs,  oro'-};  of  the  second,  VbViV;  of  the  third, 
rerH;  of  the  fourth  and 'fifth,  JHHrH;  of  the  sixth»  °6. Vo.Vi2) ;  of  the 
seventh,  o  uii.'a'i;  of  the  eighth  to  eleventh,  InrfHrl;  of  the  twelfth, 
HfctlorttHi;  ofthethirteenth'^TOTorJ-^fel;  of  the  penult, 

orHri' claws  three;  of tne  anal  5; ".'  I',  1.  °> claws  tw°-    Last  tw°  coxae 

laterally  armed. 

Gonopods  of  cf  projecting  caudad  beyond  sternite  as  a  pale  conical 
process. 

Length  9  mm. 

TYPE  LOCALITY. —  California :  Oakland. 


TAIYUBIUS  HARRIELAE  (Chamberlin). 
Plate  5,  fig.  6. 

Lithobius  harrielae  Chamberlin,  Proc.  Acad.  nat.  sci.  Phil.,  1906,  p.  3;   Ann. 

Ent.  soc.  Amer.  1909,  2,  p.  191. 
Taiyubius  harrielae  Chamberlin,  Can.  ent.,  1912,  44,  p.  176. 

DESCRIPTION. —  Dorsum  light  brown  or  testaceous,  with  a  broad 
median  longitudinal  dark  stripe  extending  the  entire  length  or  some- 
times evident  only  over  caudal  portion.  Head  testaceous,  blackish 
or  dusky  in  eye-region  and  sometimes  in  a  curved  band  along  the 
frontal  suture.  Antennae  testaceous  or  yellowish.  Prosternum  and 
prehensors  yellow  or  testaceous.  Venter  yellow,  a  few  of  the  most 
caudal  plates  darker.  Legs  light  yellow,  with  the  caudal  pairs  some- 
what darker,  sometimes  dark  brown  or  blackish  on  ectal  surface  espe- 
cially the  joints  proximad  of  tarsi. 

• 


310  BULLETIN:  MUSEUM  OF  COMPAKATIVE  ZOOLOGY. 

Body  moderately  narrowed  cephalad,  the  tenth  plate  being  clearly 
wider  than  the  head  and  slightly  wider  than  the  eighth  plate.  Third 
plate  a  little  wider  than  the  first.  Length,  in  type,  7.5  times  greater 
than  width  of  tenth  plate.  Widths  of  head  and  of  first,  third,  eighth, 
and  tenth  plates  to  each  other  as  40  : 35  : 36  : 45  : 46. 

Head  subcordate;  wider  than  long  in  ratio  17  :  16,  or  sometimes 
equal  in  length  and  breadth.  Caudal  margin  straight  or  but  slightly 
incurved.  A  transverse  furrow  more  or  less  evident  caudad  of  the 
frontal  suture,  the  furrow  or  branches  from  it  usually  angularly  bent 
caudad  at  the  middle.  The  usual  median  longitudinal  sulcus  in  front 
of  the  suture,  this  sulcus  commonly  double  with  the  parts  diverging 
cephalad.  A  median  longitudinal  furrow  on  caudal  portion  of  head 
while  from  one  to  three  curved  furrows  may  be  traced  more  or  less 
clearly  on  each  side  of  it. 

Antennae  short;  composed  of  from  thirty-three  to  forty-one  articles 
of  which  those  between  the  third  or  fourth  and  ultimate  are  short  and 
very  short  and  closely  compacted.  Hairs  of  moderate  length,  not 
dense. 

Ocelli  ten  to  fourteen  in  three  series:  e.g.,  1  +  4,  3,  2;  1  +  4,  4,  3; 
1  -f-  5,  4,  3.  Single  ocellus  much  the  largest,  vertically  oval.  The 
most  caudal  ocellus  of  top  series  largest  of  the  seriate  ocelli. 

Prosternum  1.5,  or  a  little  more,  or  less,  times  wider  than  long. 
Distance  between  chitinous  spots  2.4  times  width  at  level  of  bottom 
of  mesal  incision;  from  4  to  4.5  times  the  dental  line.  Teeth  2  +  2, 
small,  line  of  apices  clearly  recurved.  Margin  ectad  of  teeth  convexly 
rounding  ectad  and  then  caudad  as  usual.  • 

First  dorsal  plate  1.8  times  wider  than  long.  Plates  only  very 
finely  roughened,  to  the  naked  eye  appearing  nearly  smooth  and 
shining,  especially  so  the  first  one.  There  may  usually  be  traced  on 
the  major  plates  a  longitudinal  furrow  on  each  side  diverging  from  the 
median  line  caudad,  with  sometimes  traces  of  a  median  longitudinal 
furrow;  in  some  a  second  longitudinal  furrow  is  evident  ectad  of 
the  one  first  mentioned  and  toward  which  it  converges  caudad. 

Ventral  plates  without  conspicuous  markings,  to  the  naked  eye 
usually  appearing  smooth  and  shining. 

Coxal  pores  small  and  very  small:  3,  4,  4,  3;  3,  4,  5,  3;  4,  5,  5,  3; 
4,  5,  5,  4;  4,  4,  5,  4;  4,  6,  6,  5;  etc. 

Spines  of  first  legs,  MHHT  i!  of  the  second,  g-  0°'  $  \  \  or  JHHHH;  of  the 
third,  JJw  tUH  Miilii,  or  J-JJJ*;  of  the  fourth'  and  fifth, 
^\ll\  of  the  sixth  to  eleventh,  ^'2  I' I;  of  the  twelfth, 
OTTO  or  J  J-J{*;  of  the  thirteenth/ffi;'^;  of  the  penult, 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  311 


;  claws  tw°;  °f  the  anal,  JlJIo;  claws  two.  None  of  the 
coxae  laterally  armed. 

Claw  of  female  gonopods  of  moderate  size,  rather  wide,  tripartite; 
lobes  acute,  the  median  one  not  much  exceeding  the  lateral  ones. 
Basal  spines  2  +  2  or,  exceptionally  3  +  3,  the  innermost  spine  on 
each  side  in  the  latter  case  being  much  the  smallest  of  the  three; 
spines  very  broad,  widest  toward  middle  of  length,  acutely  pointed, 
shaped  somewhat  like  a  broad  arrow-head. 

Gonopods  of  male  clearly  exposed;  subtruncate  distally. 

Length  mostly  10  to  12  mm. 

TYPE  LOCALITY.  —  Colorado:    east  of  Glenwood  Springs. 

Taken  also  in  Colorado  at  Salina  and  in  Massachusetts  at  Cam- 
bridge and  Mattapan. 


TAIYUBIUS  PURPUREUS  (Chamberlin). 

Lithobius  purpureus  Chamberlin,  Proc.  U.  S.  N.  M.,  1901,  24,  p.  24. 
Taiyubius  purpureus  Chamberlin,  Can.  ent.,  1912,  44,  p.  176. 

The  original  description  of  the  types,  rearranged,  follows:  — 

Color  dark  purple-brown,  the  purple  tint  often  conspicuous  and 
unmixed.  Head  and  legs  yellowish  brown,  the  tarsal  joints  of  the 
last  pairs  of  legs  commonly  lighter;  antennae  dark,  yellow  or  rufous 
at  ends. 

Antennae  composed  of  from  twenty-eight  to  thirty-two,  articles 
which,  excepting  the  first  few,  are  short  or  very  short;  length  2.3- 
3  mm. 

Ocelli  mostly  twelve  or  thirteen. 

Prosternal  teeth  normally  2  +  2,  rather  large  and  pale  (rarely  the 
teeth  may  be  doubled). 

Coxal  pores  small  or  moderate:  2,  3,  3,  2;  3,  4,  4,  3. 

Ventral  spines  of  first  legs  0,  0,  0,  0,  1;  of  the  penult,  0,  1,  3,  3,  1; 
of  the  anal,  0,  1,  3,  3,  0  (or,  rarely,  0,  1,  3,  1,  0).  Posterior  coxae 
laterally  armed. 

Claws  of  female  gonopods  rather  long,  tripartite,  the  lobes  acute, 
with  the  median  longest  and  the  outer  one  smallest,  sometimes  near 
base  and  inconspicuous.  Basal  spines  short  and  broad,  widest  at 
middle. 

Length  7  to  8.5  mm.  Length  of  anal  legs  3-3.3  mm.;  of  antennae 
2.3-3  mm. 

TYPE  LOCALITY. —  Utah:  Salt  Lake  City. 


312  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

\ 

The  types  (U.  S.  N.  M.  786)  were  found  under  sticks,  boards,  and 
logs  laid  on  fine  loose  soil  in  and  near  growths  of  willows  on  the  banks 
of  the  Jordan  River. 

SONIBIUS  Chamberlin. 
Can.  ent.,  1912,  44,  p.  176. 

Head  with  distinct  lateral  marginal  interruptions. 

Antennae  short;    articles  normally  twenty. 

Ocelli  present;  seriate;  single  ocellus  enlarged. 

Prosternal  teeth  2  +  2  or  3  +  3;    spines  slender. 

Posterior  angles  of  ninth,  eleventh,  and  thirteenth  dorsal  plates 
strongly  produced. 

Coxal  pores  circular  or  slightly  elliptic;    uniseriate. 

Gonopods  of  male  uniarticulate. 

Claw  of  female  gonopods  short;  tripartite,  with  median  lobe  not 
much  longest.  Spines  2  +  2;  short  and  relatively  very  wide. 

Tarsi  of  anterior  legs  divided. 

Posterior  legs  of  male  without  special  lobes  or  modifications.  Third 
joint  of  all  legs  caudad  of  first  or  second  pair  with  three  dorsal  spines 
or  those  cephalad  of  sixth  with  but  two.  Fifth  joint  of  legs  between 
third  or  fourth  and  twelfth  with  two  dorsal  spines.  Dorsal  spines  of 
anal  legs  1, 0,  3, 1, 0;  ventral,  0,  1,  3,  2,  0  or  0,  1,  3,  2,  1 ;  claws  two 
or  three.  Dorsal  spines  of  penult  legs,  1,  0,  3,  1,  1 ;  ventral,  0,  1,  3,  3, 1 
or  0,  1,  3,  3,  2;  claws  two  or  three.  Dorsal  spines  of  twelfth  legs 
1,0,3,1,1  to  1,0,3,2,2;  ventral,  0,0,3,3,2.  Dorsal  spines  of 
first  legs  0,  0,  1,  1,  1  to  0, 0,  2,  2,  1 ;  ventral,  0,  0,  1,  3,  1  and  0, 0, 1,  3,  2 
toO,  0, 1,  2,  1  andO,  0,  0,  2,  1. 

.Last  two  or  three  pairs  of  coxae  laterally  armed. 

Length  8-12.5  mm. 

TYPE.—  S.  bins  (Chamberlin). 

This  genus  seems  to  be  very  close  to  Nadabius  but  differs  from  it 
especially  in  the  strongly  produced  angles  of  the  ninth,  eleventh,  and 
thirteenth  dorsal  plates  and  in  lacking  a  tibial  crest  in  the  anal  legs  of 
the  male.  It  has  thus  far  been  found  only  in  the  section  of  the 
United  States  east  of  the  Mississippi  River  and  north  of  the  Ohio 
River  (Figure  6). 

Key  to  Species  of  Sonibius. 

a.     Anal  legs  bearing  3  distinct  claws. 

b.     Dorsal  spines  of  twelfth  legs   1,  0,  3,  2,  2;    prosternal  teeth 
3  +  3;  length  of  type,  cf ,  12.5  mm.) . .  S.  bins  (Chamberlin). 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  313 


FIG.  6. —  Distribution  of  Sonibius. 


314  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

bb.     Dorsal  spines  of  twelfth  legs   1,0,3,1,1;    prosternal  teeth 

2  +  2;  length 8.5-9.5  mm S.  parvus,  sp.  nov. 

aa.     Anal  legs  bearing  only  2  distinct  claws. 

b.     Penult  legs  with  but   1   accessory  claw;    ventral   spines   of 

penult  legs,  normally  0,  1,  3,  3,  1 S.  politus  (McNeil). 

bb.     Penult  legs  with  2  accessory  claws;    ventral  spines  of  penult 
legs  normally  0, 1, 3, 3, 2 S.  numius  (Chamberlin). 


SONIBIUS  BIUS  (Chamberlin). 

JjiihoUus  Uus  Chamberlin,  Can.  ent.,  1911,  43,  p.  102. 

SoniUus  bins  Chamberlin,  Can.  ent.,  1912,  44,  p.  177;  1914,  46,  p.  302. 

DESCRIPTION. —  Dorsum  uniform  brown.  The  head  a  little  darker, 
with  the  antennae  similar  but  becoming  pale  distad.  Prosternum  like 
head,  the  prehensors  paler.  Venter  testaceous,  the  posterior  plates 
darker.  Legs  light  brown  or  testaceous  dorsally,  ventrally  paler; 
caudal  pairs  dark  proximally  but  distal  articles  yellowish  or  light 
orange. 

Body  rather  robust,  being  not  quite  seven  times  as  long  as  width 
of  eighth  and  tenth  plates  which  are  equal  in  width.  Conspicuously 
narrowed  cephalad,  with  first  plate  narrower  than  the  third.  Widths 
of  head  and  of  first,  third,  eighth,  and  tenth  plates  to  each  other  as 
46  :  40  :  42  :  52  :  52. 

Head  wider  than  long  in  about  ratio  23  :  21.  Subrotund,  the  sides 
caudally  strongly  rounded.  Caudal  margin  distinctly  incurved  mes- 
ally.  Smooth  and  shining. 

Antennae  short,  reaching  fifth  or  sixth  segment.  Articles  twenty 
(left)  —  twenty-three  (right),  moderately  long,  cylindric,  decreasing 
distad.  In  the  antenna  with  twenty-three  articles  the  distal  ones  are 
proportionately  shorter. 

Ocelli  twenty-two  in  five  series:    1  +  5,  6,  5,  5;    1  +  5,  6,  5,  3,  2. 

Prosternum  1.5+  times  wider  than  long.  Distance  between  chiti- 
nous  spots  two  times,  or  a  little  more,  greater  than  width  at  level  of 
bottom  of  median  incision;  about  3.7  times  the  dental  line.  Teeth 
3  +  3;  acute;  subequal. 

Dorsal  plates  smooth  and  shining.  Posterior  angles  of  ninth, 
eleventh,  and  thirteenth  acutely  and  strongly  produced. 

Ventral  plates  sparsely  hirsute;  the  more  caudal  ones  very  finely 
roughened.  Longitudinal  furrows  mostly  obscure.  A  wide,  shallow, 
transverse  furrow  showing  in  some  on  caudal  portion. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  315 

Coxal  pores  small,  circular:  4,  4,  5,  3;  4,  6,  5,  4. 

Spines  of  first  legs,  !Hrff4;    of  the  second,  o'o  M  2!    of  the  third, 


0.2, 1 1'>   of  the  fourth  to  ninth,  orUfi;   of  the  tenth,  J-J-J  J 1;   of 


eleventh  and  twelfth,  o,  vH;  of  the  thirteenth,  J  J  J-J-J;  of  the  penult, 
Hrl s72»  claws  three;  of  the  anal,  J  J{  J-§  or  \]  J j; -J- -§,  claws  three.  Last 
three  pairs  of  coxae  laterally  armed. 

Anal  legs  in  male  short,  the  femur  very  moderately  thickened,  com- 
planate  and  longitudinally  shallowly  furrowed  above;  the  tibia  more 
slender;  femur  shallowly  longitudinally  furrowed  above. 

Gonopods  of  male  but  little  exposed;  broad  and  short. 

Length  of  type  (cf )  12.5  mm. 

TYPE  LOCALITY. —  Michigan:    Saunders. 

Taken  also  at  Douglas  Lake,  Mich. 


SONIBIUS  PARVUS,  sp.  nov. 
Plate  6,  fig.  5. 

DESCRIPTION. —  Dorsum  brown  with  first  dorsal  plate  typically 
darker.  Head  darker,  dusky  brown,  either  with  or  without  a  dilute 
chestnut  tinge.  Antennae  dark  brown  proximally,  becoming  orange 
or  rufous  at  tips.  Prosternum  and  prehensors  testaceous.  Venter 
light  brown,  the  caudal  plates  darker.  Legs  of  nearly  same  color  as 
the  corresponding  ventral  plates,  the  last  pair  thus  darkest  but  tarsi 
of  these  orange  or  rufous. 

Body  proportionately  broad,  being  usually  only  about  6.25  times 
longer  than  width  of  tenth  plate.  Strongly  narrowed  cephalad. 
Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to 
each  other  as  49  :  44  :  48  :  58  :  60  :  60. 

Head  somewhat  wider  than  long  (49  : 46). 

Antennae  short,  the  articles  between  the  first  few  and  the  ultimate 
very  short  and  closely  united.  Ultimate  longer  than  the  two  preced- 
ing together. 

Ocelli  twelve  to  seventeen  in  three  or  four  series:  e.g.,  1  +  4,  4,  3; 
1  +  5,  5,  4,  2;  1  +  5,  4,  3,  1.  Single  ocellus  considerably  largest. 
Organ  of  Tomosvary  in  usual  position,  of  about  same  size  in  outline 
as  the  smaller  ocelli. 

Prosternum  with  incision  rather  large,  strictly  v-shaped.  Teeth 
equal  or  nearly  so,  small.  Spine  of  usual  form  and  in  usual  position. 
Sides  of  anterior  portion  of  prosternum  straight  or  nearly  so  from  spine 
caudoectad,  not  convexly  rounding  out  as  more  usual  in  the  genus; 


316  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

If  times  wider  than  long.  Distance  between  chitinous  spots  in  type 
2.6  times  width  at  level  of  bottom  of  incision;  3.55+  times  dental  line. 

First  dorsal  plate  with  sides  moderately  convex  and  caudally  con- 
verging; 1.8  times  wider  than  long.  Posterior  angles  of  ninth, 
eleventh,  and  thirteenth  dorsal  plates  strongly  acutely  produced, 
while  in  fully  grown  individuals  the  posterior  angles  of  the  seventh  and 
also  of  the  sixth  may  also  be  very  weakly  extended. 

Coxal  pores  small:  3,  4,  4,  3;  3,  4,  4,  4. 

Spines  of  first  legs,  {j-  g"  I'l'  \  or  £'  H'i4;  of  the  second,  SHrM4;  of  the 
third,  tJili;  of  the  fourth,  ftftk  of  the  fifth,  HH»  or 


» 

of  the  sixth,  \  \\-t  of  the  seventh  to  eleventh,  ^Ji;  of  the  twelfth, 
orH',  H;  of  the  thirteenth,  §•  J  \  -J  ;-|;  of  the  penult,  J  £  J  •  J  2.  claws  three; 
of  the  anal,  JJ^H01*  fcx  i  2/rl  '  the  claws  three.  'Last  two  pairs  of 


x    2/r 
coxae  laterally  armed. 

Claw  of  female  gonopods  short;  moderately  curved;  tripartite; 
median  lobe  somewhat  longest,  the  lateral  ones  subequal  and  at  same 
level  or  nearly  so,  all  acute.  Outer  basal  spine  considerably  larger 
than  the  inner  one,  broad  and  short,  the  sides  subparallel  from  base 
to  beginning  of  apical  division  which  is  very  acute,  denticulate  on  each 
side  at  base  of  apical  portion  and  sometimes  proximad  of  it.  Inner 
spine  in  ventral  view  similar  in  shape  but  proportionately  narrower 
(Plate  6,  fig.  5). 

Length  8.5  to  9.5  mm. 

'    TYPE.—  M.  C.  Z.,  No.   146.     Vermont:    Grout's  Mill,  near  Mt. 
Stratton. 

Taken  also  in  New  York  at  Big  Tupper  Lake,  St.  Lawrence  county, 
Thomas  and  F.  K.  Barbour. 


SONIBIUS  POLITUS  (McNeill). 

Lithobius  politus  McNeill,  Proc.  U.  S.  N.  M.,  1887,  10,  p.  261.     Chamberlin, 

Can.  ent.,  1911,  43,  p.  103. 

Lithobius  howei  Bollman  (ad.  part  max.),  Proc.  U.  S.  N.  M.,  1889,  11,  p.  409. 
Sonibius  politus  Chamberlin,  Can.  ent.,  1912,  44,  p.  177;   1920,  52,  p.  95. 

DESCRIPTION. —  Dorsum  brown,  uniform  or  nearly  so.  Head 
either  nearly  same  as  dorsum  or  considerably  darker.  Antennae 
brown,  having  often  a  reddish  or  purplish  tinge  proximally,  paler 
distad;  in  one  specimen  the  first  article  is  very  much  lighter  than 
those  immediately  succeeding.  Venter  testaceous,  the  anterior  plates 
almost  clear  yellow.  Prosternum  testaceous,  the  prehensors  paler. 


CHAMBERLIN :   NORTH   AMERICAN    LITHOBIIDAE.  317 

Legs  like  corresponding  parts  of  venter,  caudal  pairs  a  little  darker 
proximally  but  dilute  orange  distally. 

Body  proportionately  rather  wide  being  mostly  about  7  times 
longer  than  the  width  of  the  tenth  plate.  Body  moderately  narrowed 
cephalad  and  the  first  plate  clearly  narrower  than  the  third.  Widths 
of  head  and  of  first,  third,  eighth,  and  tenth  plates  to  each  other  as 
37  :  35  :  37  :  43  :  43. 

Head  wider  than  long  in  nearly  ratio  14  :  13.  Sides  caudad  of  eyes 
nearly  straight  excepting  in  front  of  caudal  corners,  where  more  convex. 
Caudal  margin  mesally  incurved.  Marginal  breaks  not  especially 
conspicuous.  Smooth  and  shining. 

Antennae  short,  reaching  in  most  only  to  the  fifth  or  to  edge  of 
sixth  segment.  Articles  twenty,  mostly  short,  decreasing  distad 
gradually,  or,  in  some,  those  distad  of  the  first  six  to  eight  abruptly 
shorter. 

Ocelli  fifteen  to  twenty  in  mostly  four  series:  e.g.,  1  +  2,  3,  4,  5; 
1  +  5,  5,  3,  2.  Single  ocellus  much  the  largest,  oval. 

Prosternum  1.5  times  wider  than  long.  Distance  between  chitinous 
spots  3.7  to  a  little  less  than  4  times  the  dental  line;  between  2.5  and 
2.7  times  width  at  level  of  bottom  of  mesal  incision.  Sides  of  anterior 
portion  slanting  almost  directly  from  outer  teeth.  Teeth  small, 
acute,  with  line  of  apices  conspicuously  reentrant;  2  +  2  or  3  +  3,  in 
the  latter  case  the  most  mesal  tooth  on  each  side  commonly  very  small. 

Dorsal  plates  smooth  and  shining.  Hairs  short  and  sparse,  more 
numerous  on  caudal  plates. 

Ventral  plates  appearing  smooth  and  shining,  or  under  lens  some 
are  seen  to  be  finely  roughened,  especially  the  more  caudal  ones. 
Hairs  more  numerous  caudad. 

Coxal  pores  of  medium  size,  circular  or  slightly  transversely  elliptic: 
4,  6,  6,  5;  4,  6,  6,  6;  5,  6,  6,  6;  4,  5,  5,  4. 

Spines  of  first  legs,  O'TTT  or  o'  \ll\  of  the  second,  S^JJ  i  or  J  g;  J  I,  \; 
of  the  third,  o'ol'^;  of  the  fourth  to  tenth,  £  J  J  J-f;  of  the  eleventh, 
SHBrH;  of  the  twelfth,  JJJU:  of  the  thirteenth,  Hl\,\;  of  the 
penult,  oiiJJ'L  claws  three,  of  which  the  anterior  accessory  is  very 
small ;  of  the  anal,  J  J  J  J-jj  or  J  J-J-£  J,  claws  two  or  a  third  represented 
by  an  obsolete  point.  Last  two  or  three  pairs  of  coxae  laterally 
armed. 

Posterior  legs  of  male  short  and  slender;  the  tibia  and  femur  of 
both  anal  and  penult  pair  shallowly  longitudinally  furrowed  above. 

Gonopods  of  male  exposed  as  moderately  large  rounded  or  hemi- 
spherical eminences  bearing  two  or  three  bristles. 


318  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Gonopods  of  female  considerably  exceeded  by  dorsal  plate  of  anal 
segment.  Claw  short  and  relatively  wide;  tripartite;  the  lobes  short 
and  the  median  not  much  longer  than  the  others.  Basal  spines  short 
and  proportionately  very  wide,  with  sides  subparallel  to  the  distal 
third  or  fourth  which  is  acuminate  with  apical  angle  low  or  obtuse. 

Length  8  to  11  mm. 

TYPE  LOCALITY. —  Indiana:  Dublin. 

Taken  also  in  Indiana:  at  Bloomington,  Kokomo  (Bollman  coll.). 
Michigan:  Ludington.  Illinois:  Peoria.  Ontario,  Ottawa,  Quebec. 

Mr.  Bollman  appears  undoubtedly  to  have  applied  his  name  Litho- 
bius howei  to  two  entirely  different  species.  The  type  of  howei  is  a 
male  from  Fort  Snelling,  Minn.,  and  an  examination  of  this  shows  it  to 
be  closely  related  to,  and  possibly  identical  with,  L.  mordax  and  to 
differ  widely  from  the  present  species.  In  Bollman's  second  and 
somewhat  fuller  account  of  the  species  (Proc.  U.  S.  N.  M.,  1887,  10, 
p.  255  and  258)  he  gives  the  anal  legs  as  having  but  one  claw,  with 
ventral  spines  1,  3,  3,  1  and  length  7  mm.;  ventral  spines  of  first  legs 
2,  3,  2;  ocelli  25  in  number;  total  length  15  mm.,  etc.;  all  of  which 
points  separate  it  clearly  from  politus;  politus  is  first  described  in  this 
same  paper  under  the  heading  Lithobius  politus  McNeill  MSS.,  and  is 
reported  from  Dublin  and  Bloomington,  Indiana,  and  from  Luding- 
ton, Mich.  However,  in  Mr.  Bollman's  Catalogue  of  the  Myriopods 
of  Indiana"  (Proc.  U.  S.  N.  M.,  1888, 11)  and  in  his  posthumous  Cata- 
logue of  North  American  Myriapoda,  politus  is  not  mentioned,  while 
howei  is  listed  from  Dublin,  Bloomington,  and  Kokomo.  An  exami- 
nation of  the  specimens  from  these  localities  in  Mr.  Bollman's  collec- 
tion labeled  as  L.  howei  show  them  to  be  the  same  as  politus.  It  is 
thus  evident  that  Mr.  Bollman  intended  to  drop  politus  as  a  synonym 
of  howei;  but  that  the  two  species  are  widely  different  is  evident  from 
the  original  descriptions,  even  though  the  presumed  type  of  howei 
in  the  National  Museum,  which  does  not  agree  wholly  with  the 
description,  might  be  regarded  as  possibly  incorrectly  labeled. 


SONIBIUS  NUMIUS  (Chamberlin). 

Lithobius  numius  Chamberlin,  Can.  ent.,  1911,  43,  p.  102.  • 

Sonibius  numius  Chamberlin,  Can.  ent.,  1912,  44,  p.  177. 

DESCRIPTION. —  Dorsum  nearly  uniform  brown.  Head  darker. 
Antennae  brown  or  reddish  brown  proximally,  paler  distad.  Venter 
testaceous.  Caudal  legs  dilute  orange  distad. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  319 

Body  in  type  seven  times  longer  than  width  of  tenth  plate;  more 
strongly  narrowed  cephalad  than  in  politus.  Widths  of  head  and  of 
first,  third,  eighth,  tenth,  and  twelfth  plates  to  each  other  as  36  :  33  : 
35  :  43  :  43. 

Head  considerably  wider  than  long  (12  :  11);  broadly  subcordate; 
caudal  margin  mesally  distinctly  incurved. 

Antennae  short,  reaching  the  fifth  segment.  Articles  of  moderate 
length,  decreasing  regularly  distad.  Hairs  of  moderate  length,  sub- 
dense. 

Ocelli  twenty  to  twenty-three  in  five  series:  e.g.,  1  +  2,  5,  5,  5,  4; 
1  +  3,  5,  5,  4,  2.  Single  ocellus  oval,  large. 

Prosternum  about  1.5  times,  or  a  little  more,  wider  than  long. 
Distance  between  chitinous  spots  2.8  times  width  at  level  of  bottom 
of  incision,  a  little  less  than  4.5  times  as  great  as  the  dental  line. 
Teeth  2  +  2,  small,  acute,  the  line  of  apices  reentrant.  Spine  almost 
contiguous  with  ectal  tooth,  bristle-like. 

Coxal  pores  in  type:  4,  6,  6,  5. 

Spines  of  first  legs,  ^I'l'l  or  JJJ-J--};  of  the  second,  J-J-*£-}  or 
gfff-1;  of  the  third,  S^'il;  of  the  fourth,  g'Siai;  of  the  fifth  to 
eleventh,  UK  a*  of  the  twelfth,  ^-J-J-g;  of  the  thirteenth,  JHrH; 
of  the  penuit,  JJJJJ,  claws  three;  of  the  anal,  Sti/^cl  claws  two. 
Last  two  pairs  of  coxae  laterally  armed. 

Claw  of  female  gonopods  short;  tripartite;  lobes  short  with  the 
median  but  little  longer  than  the  others.  Spines  broad;  sides  sub- 
parallel  or  a  little  diverging  to  acuminate  apical  portion,  outer  longer 
than  inner;  larger  than  in  politus. 

Length  of  type  ( 9  )  10.5  mm. 

TYPE  LOCALITY. —  Wisconsin:    Haugen. 

Very  close  to  the  preceding  species  and  may  possibly  prove  to  be 
only  a  variety  of  it. 

NADABIUS  Chamberlin. 
Bull.  M.  C.  Z.,  1913,  67,  p.  62. 

Head  with  distinct  marginal  breaks. 

Antennae  short  or  very  short;  articles  nineteen  to  twenty-three, 
but  normally  twenty. 

Eye  consisting  of  ocelli  arranged  in  from  three  to  five  series;  single 
ocellus  enlarged. 

Prosternal  teeth  2  +  2,  or  occasionally  3  +  3  and  4  +  4;  line  of 
apices  more  or  less  recurved. 


320  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Posterior  angles  of  none  of  the  dorsal  plates  produced  or  those  of 
eleventh  and  thirteenth  weakly  so. 

Coxal  pores  circular;   uniseriate:  3,  4,  4,  3  to  5,  6,  6,  5. 

Gonopods  of  male  uniarticulate;  bearing  from  two  to  four  long 
bristles. 

Claw  of  female  gonopods  tripartite,  or  rarely  entire  by  obliteration 
of  lateral  teeth.  Basal  spines  2  +  2,  typically  short  and  rather  broad 
with  sides  proximad  of  apical  acuminate  portion  subparallel  or  slightly 
diverging  from  base  distad.  First  article  of  gonopod  not  excavated 
proximally. 

Tarsi  of  all  legs  divided. 

In  the  male  the  anal  legs  are  short  and  but  little  thickened;  dorsally 
longitudinally  more  or  less  sulcate;  the  fifth  joint  bearing  a  character- 
istic low  crest  at  the  distal  end  mesad  of  median  line,  the  crest  bearing 
a  variable  number  of  hairs,  usually  of  special  type. 

Last  one  to  three  pairs  of  coxae  laterally  armed.  Third  joint  of  all 
legs  caudad  of  second  with  either  two  or  three  dorsal  spines,  the 
number  bearing  two  variable.  Fifth  joint  of  all  legs  between  first  or 
second  and  twelfth  with  two  dorsal  spines.  Dorsal  spines  of  anal 
legs  1,  0,  3,  1,  0;  ventral,  0,  1,  3,  3,  1  to  0,  1,  3,  2,  0;  claws  1  or  2. 
Dorsal  spines  of  penult  legs  1,  0,  3,  1,  1;  ventral,  0, 1,  3,  3,  2;  claws 
three  or,  less  commonly,  two.  Dorsal  spines  of  thirteenth  legs 
1, 0,  3, 1,  1  or  1,  0,  3,  2,  2;  ventral  0,  1,  3,  3,  2  or  0,  0,  3,  3,  2.  Dorsal 
spines  of  twelfth  legs  1,  0,  3,  2,  2  or  rarely  only  1,  0,  3,  1,  1,  the  coxal 
spine  sometimes  missing;  ventral  0,  0,  3,  3,  2  or  0,  0,  2,  3,  2.  Dorsal 
spines  of  eleventh  legs  0,  0,  3,  2,  2;  ventral  0,  0,  2,  3,  2  or  0,  0,  3,  3,  2. 
Dorsal  spines  of  first  legs  0,  0,  2,  2,  1  to  0,  0,  3,  2, 1  and  0,  0,  3,  2,  2; 
ventral  0,  0,  1,  2,  1  to  0,  0,  2,  3,  2. 

Length  7  to  16  mm.  but  mostly  above  10  mm. 

TYPE. —  N.  iowensis  (Meinert). 

The  species  of  Nadabius  are  for  the  greater  part  of  medium  size, 
prevailingly  brown  or  chestnut  in  color  with  the  head  darker.  In  the 
north  central  states  they  are  the  most  abundant  in  individuals  of  the 
Lithobiidae. 

Key  to  Species  of  Nadabius. 

a.     Anal  leg  with  2  distinct  claws. 
b.     Dorsal  spines  of  thirteenth  legs  1,  0,  3,  2,  2;  only  the  last  pair 

of  coxae  laterally  armed. 

c.     Prosternal  teeth  2  +  2 ;   ventral  spines  of  anal  legs  normally 
0,  1,  3,  3,  0 N.  puttus  (Bollman). 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  321 


7. —  Distribution  of  Nadabius. 


322  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

cc.    Prosternal  teeth  4  +  4  or  sometimes  3  +  3;   ventral  spines 

of  anal  legs  normally  0,  1,  3,  3,  1..  .N.  aristeus,  sp.  nov. 

bb.     Dorsal  spines  of  thirteenth  legs  1,  0,  3,  1,  1;   last  2  pairs  of 

coxae  laterally  armed. 
c.    Ventral  spines  of  anal  legs  0,1,3,2,0;    dorsal  spines  of 

twelfth   legs  0,  0,  3, 1,  1 N.   oreinus,   sp.   nov. 

cc.    Ventral  spines  of  anal  legs  0, 1,  3,  3,  0  or  0,  1,  3,  3,  1;  dorsal 
spines  of  twelfth  legs  1,  0,  3,  1,  2  or  0,  0,  3,  1,  2. 

N.  coloradensis  (Cockerell). 
aa.     Anal  leg  with  but  1  claw. 

6.     Dorsal  spines  of  thirteenth  legs  1,  0,  3, 1,  1. 
c.     Dorsal   spines   of   twelfth  legs    1,  0,  3,  1, 1. 

N.  mesechinus  (Chamberlin). 
cc.     Dorsal  spines  of  twelfth  legs  1,  0,  3,  2,  2  to  0, 0,  3,  2,  2  and 

0,  0,  3, 1,  2. 

d.    Prosternal  teeth  3  +  3  or  4  +  4 ....  N.  iowensis   (Meinert). 
dd.    Prosternal  teeth  2  +  2  or  rarely  2  +  3. 

N.  eigenmanni  (Bollman). 
bb.     Dorsal    spines    of   thirteenth   legs,    1,0,3,2,2. 

N.  holzingeri  (Bollman). 


NADABIUS  ARISTEUS,  sp.  nov. 
Plate  6,  fig.  3,  4. 

DESCRIPTION. —  Dorsum  brown ;  a  darker  median  longitudinal 
stripe  more  or  less  evident.  Head  and  first  dorsal  plate  much  darker, 
almost  black.  Antennae  very  dark,  brown  to  blackish,  proximally, 
becoming  paler  and  more  or  less  rufous  distally.  Prosternum  like 
head;  prehensors  rufous  distally.  Venter  light  brown  or  testaceous, 
darker  caudally.  Legs  light  brown,  caudal  pairs  somewhat  darker. 

Body  robust  only  6  to  7  times  longer  than  width  of  tenth  plate. 
Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  dorsal 
plates  to  each  other  as  90  :  78  : 83  : 102  : 101  : 98. 

Head  subcordate,  widest  at  level  of  breaks  which  are  pronounced 
and  rectangular.  Wider  than  long  in  about  ratio  15  : 14. 

Antennae  moderately  short.  Articles  twenty  to  twenty -one;  of 
intermediate  length,  subcylindric,  decreasing  distad.  Ultimate  article 
shorter  than  the  two  preceding  taken  together. 

Ocelli  twelve  to  eighteen  in  three  or  four  series:  e.g.,  1  +  4,  4,  3; 
1  +  4,  3,  3,  1;  1  +  4,  4,  4,  3;  1  +  4,  5,  4,  3.  Single  ocellus  clearly 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  323 

exceeding  any  other  in  size,  or  in  largest  specimens  not  greatly  differing 
from  most  caudal  ocellus  of  dorsal  series. 

Prosternal  teeth  4  +  4,  rarely  3  +  3,  acute,  the  most  mesal  on  each 
side  smallest.  Incision  small,  between  v-  and  u-shaped.  Spine 
slenderly  acuminate  (Plate  6,  fig.  4).  In  type  1.6  times  wider  than 
long.  Distance  between  chitinous  spots  2  times  width  at  level  of 
bottom  of  median  incision;  2.8  times  the  dental  line. 

First  dorsal  plate  widest  anteriorly;  sides  convex,  converging 
moderately  caudad;  1.7—  times  wider  than  long.  Posterior  corners 
of  ninth  plate  rectangular  or  a  little  rounded;  those  of  the  eleventh 
a  little  produced,  those  of  the  thirteenth  more  strongly  so. 

Coxal  pores:  4,  5,  5,  5;   circular  or  in  part  transversely  subelliptic. 

Spines  of  first  legs,  %$£#  or  J  J  J  J  J;  of  the  second,  J  J-J  J-J  or  $$#; 
of  the  third,  J-S-JS-J  to  tJJJJ;  of  the  fifth,  "-jtfJJ;  of  the  sixth, 
SStll  or  JJJH;  of  the  seventh, JJJi*,  JJjJi  or  KJ-JJ;  of  the 
eighth  and  ninth,  ffiffi;  of  the  tenth,  X'lll  or  H' 2  3 ';  of  the 
eleventh  and  twelfth, 'j'j'jtj;  of  the  thirteenth,  o;J  JJ-|  or  jftfti;  of 
the  penult,  o7vij7O>  °r  occasionally  oiii^vL  claws  three;  of  the  anal, 
o!x3.3!i»  claws  two.  Anal  coxae  laterally  armed. 

Tibia  of  anal  leg  in  male  with  a  sharp  edged  dorsal  longitudinal 
ridge  showing  at  its  distal  end  the  usual  crest  which  is  low  and  not 
much  elevated  distad. 

Gonopods  of  male  distinctly  exposed;  distally  rounded;  bearing 
two  bristles. 

Claw  of  female  gonopods  short  and  broad,  tripartite,  with  the 
median  not  much  larger  in  size  than  the  dorsal,  these  two  bluntly 
rounded  and  short,  the  ventral  tooth  smaller  and  more  proximal  in 
position.  Spines  proportionately  very  short,  broad,  but  little  nar- 
rowed from  base  to  distal  division  which  is  short  and  apically  rounded. 

Length  11  to  16  mm.  A  male  11.5  mm.  long  has  antennae  4  mm. 
and  anal  leg  4.2  mm.,  with  tenth  plate  cir.  1.9  mm.  wide. 

Praematurus. —  Coloration  as  in  maturus,  or  a  little  lighter  through- 
out. 

Antennae  short;  articles  twenty  (on  one  side  in  one  specimen  only 
seventeen). 

Ocelli  1  +  4,  3,  3;   1  +  4,  4,  3.     Relations  as  in  adult. 

Prosternal  teeth  small  3  +  3.     Incision  widely  v-shaped. 

Coxal  pores:  3,  4,  4,  3;  very  small. 

Claw  of  female  gonopods  very  short,  thin,  bilobed  or  trilobed  with 
the  outer  lobe  very  small  and  the  inner  lobe  blunt.  Spines  2  +  2, 
but  the  inner  one  of  each  pair  minute,  appearing,  in  specimens  de- 


324  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

scribed,  as  a  mere  point;  the  outer  spine  already  rather  robust  though 
proportionately  more  slender  than  in  the  adult. 

Spines  of  first  legs,  oo^i  i;  of  the  second  and  third,  Jnrm;  of  the 
fourth  and  fifth,  otHS'ii    of  the  sixth  to  eleventh,  Jifffe    of  the 
twelfth,  KJiJ;    of 'the  thirteenth,  J-J-JJI  or  J-J  \ %  \  • '  of '  the  anal, 
iHrlari-     Last  pair  of  coxae  laterally  armed. 
'  Length  10-11  mm.     (Ithaca,  N.  Y.). 

TYPE. —  M.  C.  Z.,  No.  247,  New  Jersey:    Macapin,  November, 
1913  (J.  H.  Emerton). 

Taken  also  in  New  York  at  Ithaca,  and  in  Massachusetts  at  Wor- 
cester. 


NADABIUS  PULLUS  (Bollman). 
Plate  7,  fig.  1-3. 

Lithobius  pullus  Bollman,  Amer.  nat.  1887,  21,  p.  81.  Proc.  U.  S.  X.  M.,  1887, 
10,  p.  257.  1888,  11,  p.  409.  Bull.  46,  U.  S.  N.  M.,  1893,  p.  19,  21,  24, 
110,  134.  Chamberlin,  Can.  ent.,  1911,  43,  p.  103. 

Lithobius  elattus  Bollman,  Proc..  U.  S.  N.  M.,  1889,  11,  p.  348.  Chamberlin, 
Ann.  Ent.  soc.  Amer.,  1911,  4,  p.  40. 

DESCRIPTION. —  Dorsum  brown.  Head  darker,  mostly  somewhat 
chestnut.  Prosternum  dark  brown,  the  prehensors  lighter.  Venter 
paler  than  dorsum.  Legs  similar  to  venter;  posterior  pairs  light 
distally  as  usual. 

Body  in  types  described  7.66  to  8  times  longer  than  width  of  teeth 
plate.  Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth 
plates  to  each  other  as  33  : 29  : 31  : 39  :  39  : 37. 

Head  precisely  equal  in  length  and  breadth,  or  very  nearly  so. 
Lateral  margin  a  little  incurved  midway  between  break  and  caudal 
corner,  the  latter  widely  rounded. 

Antennae  short  or  very  short,  commonly  reaching  only  upon  fifth 
body  segment.  Articles  normally  twenty,  these  moderately  short. 

Ocelli  mostly  near  ten  or  eleven  in  three  or  four  series:  e.  g.,  1  -f-  4, 
3,  2;  1  +  4,  3,  3;  and  1  +  4,  3,  2,  1,  a  common  arrangement.  Eye- 
patch  subtriangular,  with  apex  ventrad.  Of  the  seriate  ocelli  the  first 
one  of  the  top  series  is  largest  as  usual,  the  others  not  much  differing 
in  size  excepting  the  most  ventral,  which  may  be  considerably  reduced. 

Prosternal  teeth  2  +  2,  of  moderate  size,  equal,  acute.  Spine 
long,  stout  at  base  but  distally  slender  and  acute.  In  type  measured, 
prosternum  is  1.52  times  wider  than  long.  Distance  between  chitin- 


CHAMBERLIX:    XORTH   AMERICAN    LITHOBIIDAE.  325 

ous  spots  2.2 —  times  width  at  level  of  bottom  of  median  incision  and 
3.7  times  the  dental  line. 

First  dorsal  plate  1.65  times  wider  than  long.  Posterior  angles  of 
none  of  the  dorsal  plates  at  all  produced. 

Coxal  pores  rather  small,  circular:  3,  4,  4,  3;  4,  5,  5,  5. 

Spines  of  first  legs,  JJ-JH  of  the  second,  JJJH  or  JJftJ;  of 
the  third  to  seventh,  J-J  *  J-*  or  J  °0;  J  J  *;  of  the  eighth,  ^ffibl  to  J  J  |1;  J; 
of  the  ninth,  J  J 1 1 2  or  J-J  J-J-|;  of  the  tenth  to  twelfth,  ttttlJ  of  the 
thirteenth,  o^JJ;!;  of  the  penult,  oiiil^i  claws  two,  with  the  acces- 
sory one  large;  of  the  anal,  JfJiift  very  rarely  JJ-JJ-J,  claws  two. 
Last  pair  of  coxae  laterally  armed. 

Anal  leg  of  male  short,  moderately  thickened;  fifth  joint  at  distal 
end  on  dorsal  surface  and  toward  mesal  side  with  a  low  keel-like  crest 
which  is  most  elevated  distad;  third,  fourth  especially,  and  the  fifth 
joints  longitudinally  furrowed  dorsally.  In  the  female  the  last  two 
pairs  of  legs  are  enlarged  and  furrowed  as  in  the  male  but  the  anal  pair 
lack  the  crest  on  fifth  joint. 

Gonopods  of  male  cuneate;  each  bearing  three  long  bristles. 

Claw  of  female  gonopods  short  and  broad;  distinctly  tripartite, 
with  the  middle  lobe  longer  and  more  acute  than  the  lateral.  Basal 
spines  short  and  relatively  very  broad;  distally  acutely  rounded; 
inner  spine  a  little  smaller  than  the  outer,  its  principal  plane  set  almost 
at  right  angles  to  that  of  the  outer  and  its  edge  being  thus  presented 
ventrad. 

Length  9-12  mm.  a  male  11.5  mm.  long,  has  antenna  5  mm.  long, 
anal  leg  3.6  mm.  long,  and  tenth  plate  1.4+  mm.  wide. 

TYPE    LOCALITY. —  Indiana:     Bloomington. 

Taken  also  in  Illinois  at  Dwight.  Tennessee:  Johnson  City, 
Russell ville.  Virginia:  Chatham,  Lynchburg,  Natural  Bridge,  Bal- 
cony Falls,  Marksville.  "West  Virginia:  White  Sulphur.  D.  C.: 
Washington. 

The  description  above  is  based  chiefly  upon  a  pair  of  the  cotypes 
from  Bloomington. 

XADABIUS  OREIXUS,  sp.  nov. 
Plate  5,  fig.  7;  Plate  6,  fig.  1. 

DESCRIPTION. —  Brown.  The  head  in  front  of  suture  paler. 
Antennae  brown,  yellow  at  tips.  Prosternum  brown,  prehensors 
yellowish.  Venter  pale,  of  very  dilute  olivaceous  cast,  the  last  several 
plates  much  darker.  Legs  yellowish. 


326  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  65  :  59  :  60  :  70  :  72  :  69. 

Head  subcordate,  conspicuously  narrowed  forward  from  a  little 
behind  eyes.  Marginal  breaks  distinct  but  oblique.  Wider  than 
long  in  about  ratio  65  :  60. 

Antennae  short.  The  first  four  or  five  articles  rather  long,  the 
others  gradually  decreasing  in  length  distad.  Ultimate  article  longer 
than  the  two  preceding  together. 

Ocelli  in  type  fifteen  or  sixteen  in  three  series:  thus,  1  +  6,  5,  3; 
1  +  6,  5,  4.  Single  ocellus  largest,  subelliptic. 

Prosternum  1.62  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.47  times  width  at  level  of  bottom  of  sinus;  4^  times  the 
dental  line.  Sinus  narrowly  v-shaped.  Line  of  apices  of  teeth  nearly 
straight,  the  inner  tooth  being  a  little  larger  than  the  outer.  Spine 
long  and  slender,  bristle-like  distally.  Sides  ectad  of  bristle  convex. 

First  dorsal  plate  only  slightly  narrowed  caudad,  the  posterior 
corners  strongly  rounded  as  usual;  caudal  margin  mesally  incurved; 
1.68  times  wider  than  long.  Caudal  margin  of  ninth  plate  straight  or 
with  ends  slightly  bent  caudad.  Posterior  angles  of  eleventh  and 
thirteenth  dorsal  plates  weakly  produced. 

Coxal  pores:  3,  4,  4,  4-4,  4,  4,  4. 

Spines  of  first  legs,  o'o  M'J;  of  the  second,  o'o  i'!-';  of  the  third  to 
eleventh,  J-J-JJ|;  of  the  twelfth,  J-JJ-H;  of  the' thirteenth,  ££«££; 
of  the  penult,  ^-jHJ; £4  claws  three;  of  the  anal,  oHHHi~u>  claws  two. 
Last  two  pairs  of  coxae  laterally  armed. 

Claw  of  female  gonopods  short  and  broad;  tripartite,  teeth  distinct 
and  acute,  sometimes  a  fourth  tooth  present  on  mesal  side.  Basal 
spines  relatively  short  and  very  broad;  in  ventral  view  the  outer  one 
is  considerably  broadest,  widening  from  base  to  the  acutely  acuminate 
distal  portion  (Plate  6,  fig.  1). 

Immaturity. —  Very  pale,  the  head  with  the  antennae  and  several 
most  caudal  plates  yellowish.  Posterior  legs  dorsally  nearly  white. 

Antennae  already  with  the  twenty  articles  present,  those  between 
the  third  and  the  ultimate  relatively  shorter  than  in  the  maturus. 

Ocelli  1  +  3,  3,  pale.  Single  ocellus  a  little  larger  than  the  most 
caudal  one  of  upper  series.  Seriate  ocelli  conspicuously  decreasing 
in  size  cephalad. 

Prosternum  as  in  adult. 

Coxal  pores  2,  2,  3,  2. 

Gonopods  of  female  short.  The  three  articles  developed.  Claw 
appearing  as  a  slender  spine-like  chitinous  process  which  is  entire 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  327 

and  slightly  curved  at  tip.  Distal  article  bearing  a  single  ventral 
bristle,  the  second  article  two,  and  the  first  also  two.  Spines  1  +  1 ; 
moderately  wide  proximally,  acuminate  from  near  middle  of  length. 

Spines  of  first  legs,  oro/H;  of  tne  second  and  third,  J-J-^fi;  of  the 
fourth  and  fifth,  KoHH;  of  tne  sixth,  SSzri;  of  the  seventh  and 
eighth,  o'°'Hri;  of  the  ninth  (regenerated),  o'o'i'H;  of  the  tenth, 
(HHHH;  of  the  eleventh,  H$ti;  of  the  twelfth^  0^1x2;  of  the 
thirteenth,  H^i;  of  the  penult,  JlSJ-z  or  J-J-Ji;}  (on  one  side);  of 
the  anal,  JiiJ/o-  Last  two  pairs  of  coxae  laterally  armed. 

Length  cir.  5.5.  mm. 

TYPE. —  M.  C.  Z.,  No.  271.  California:  Shasta  Springs,  August, 
1909. 

The  male  of  this  species  is  unknown. 


NADABIUS  COLORADENSIS  (Cockerell). 
Plate  7,  fig.  4. 

Lithobius  kochii  var.  coloradensis  Cockerell,  Trans.  Amer.  ent.  soc.,  1893,  20, 

p.  370. 

Lithobius  kochii  Bollman  (non  Stuxberg),  Proc.  U.  S.  N.  M.,  1889,  11,  p.  349. 
Lithobius  dopaintus  Chamberlin,  Can.  ent.,  1911,  43,  p.  69. 
Lithobius  coloradensis  Chamberlin,  Can.  ent.,  1911,  43,  p.  70. 

DESCRIPTION. —  Dorsum  testaceous  to  brown.  Head  dilute  chest- 
nut, commonly  darkest  caudad  of  suture.  Antennae  brown  proxi- 
mally, becoming  rufous  or  yellowish  distad.  Prosternum  brown,  the 
prehensors  paler.  Venter  greyish  yellow  to  dilute  brown,  the  caudal 
plates  somewhat  more  deeply  pigmented  as  usual.  Legs  yellowish 
grey  or  dilute  greyish  brown,  the  posterior  pairs  more  strongly  pig- 
mented, often  light  ferruginous  or  orange. 

Body  from  8.5  to  9  times  longer  than  width  of  tenth  plate,  commonly 
toward  the  latter  limit.  Widths  of  head  and  of  first,  third,  eighth, 
tenth,  and  twelfth  plates  to  each  other  as  33  :  31  :  33-  :  39  :  36. 

Head  considerably  wider  than  long  (10  :  9).  Sides  convex  between 
eyes  and  marginal  breaks,  behind  breaks  conspicuously  converging 
caudad,  weakly  excurved. 

Antennae  short,  mostly  reaching  to  the  fifth  segment,  more  rarely 
to  the  sixth.  Composed  of  nineteen  to  twenty-three  articles,  twenty 
being  the  usual  number.  Articles  short,  cylindric,  or  each  only  slightly 
enlarging  distad. 


328  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Ocelli  ten  to  fifteen  in  three  or  four  series:  e.g.,  1  +  4,  3,  2;  1+4, 

3,  3;  1  +  4,  4,  3;  1  +  4,  4,  3, 1;  1  +  2,  5,  3,  5;  1  +  3,  5,  3,  3;  1  +  2, 

4,  3,  2. 

Prosternum  in  measured  specimen  1.64  times  wider  than  long. 
Distance  between  chitinous  spots  2.4  times  the  width  at  level  of  bot- 
tom of  sinus;  4  times  the  dental  line.  Teeth  2  +  2,  rather  small, 
acute;  line  of  apices  recurved.  Spines  much  stouter  proximally  than 
the  bristles,  abruptly  and  characteristically  narrowed  near  middle, 
the  distal  portion  bristle-like.  Median  incision  widely  rounded  at 
bottom,  shallow. 

First  dorsal  plate  1.9+  times  wider  than  long;  the  sides  convex,  con- 
siderably converging  caudad;  caudal  corners  strongly  rounded. 
Plates  polished  but  under  lens  showing  a  very  fine  tuberculation  or 
roughening.  Angles  of  none  of  the  dorsal  plates  at  all  produced. 

Anterior  ventral  plates  nearly  smooth,  the  plates  caudad  becoming 
more  roughened  and  showing  a  more  distinct  median  sulcus,  this 
being  deepest  on  the  last  two  sternites. 

Coxal  pores  of  moderate  size  to  small,  circular:  3,  4,  4,  4;  3,  4,  4,  3; 
4,4,4,4;  4,5,5,4;  4,6,6,5. 

Spines  of  first  legs,  ftJtB  onBHH  or  tfHfj  of  the  second  to  eighth, 

-f -f \;  of  the  ninth  to  eleventh,  o;  27372  or  iHHtHl  of  tne  twelfth, 
;  of  the  thirteenth  and  penult,  ££J |:1  'claws  two;  of  the  anal, 
O  °r  HHBri»  claws  two.  Last  two  pairs  of  coxae  laterally  armed. 

Anal  legs  short  and  rather  slender.  In  the  male  the  third,  fourth, 
and  fifth  articles  are  dorsally  longitudinally  furrowed;  fifth  article  at 
distal  end  in  usual  place  elevated  into  a  low  and  rather  broad  crest 
similar  to  that  of  iowcnsis  but  lower  and  less  conspicuous. 

Gonopods  of  male  very  short;  bearing  one  or  two  bristles,  the  latter 
being  apparently  the  normal  number. 

Claw  of  female  gonopods  short  and  relatively  wide;  tripartite,  the 
three  divisions  distinct  and  subequal  or  the  median  usually  a  little 
longer  than  the  others.  Spines  short  and  stout,  the  outer  somewhat 
larger  than  the  inner,  in  ventral  view  with  sides  parallel  or  a  little 
diverging  to  about  distal  third  or  fourth  of  length,  then  abruptly 
narrowing  and  acuminate;  wider  surface  of  inner  spine  more  or  less 
oblique  to  that  of  the  outer  one. 

Length  10  to  15  mm.  A  male  12.5  mm.  long  has  antennae  3.5  mm. 
long;  anal  leg  4.25  mm.  long;  and  tenth  plate  1.42  mm.  wide. 

Praematurus. —  Color  not  evident  in  specimen  described. 

Antennae  very  short;  articles  twenty.  * 

Ocelli  1  +  3,  3;   1  +  4,  2.     Caudal  ocellus  of  upper  row  largest. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  329 

Prosternum  nearly  as  in  maturus,  teeth  small  and  acute.  1.6  times 
wider  than  long. 

Coxal  pores  very  small,  circular:  2,  2,  3,  3;  3,  3,  3,  3. 

Claw  of  female  gonopods  short  and  wide,  three  or  only  two  teeth 
evident.  Basal  spines  2  +  2,  the  inner  of  each  pair  much  shorter  and 
more  slender. 

Anal  legs  in  male  with  fourth  and  fifth  articles  showing  the  longi- 
tudinal sulcation  dorsally  but  the  tibial  crest  only  faintly  or  not  at  all 
indicated. 

Ventral  spines  of  first  legs  0,  0,  1,  1,  1.  Spines  of  second  and  third 
legs,  JtJ-J-J;  of  the  fourth,  JHtifl  or  KrHi;  of  the  fifth,  JH^f;  of 
the  sixth  and  seventh,  JJ-JJ-i;  of  the  eighth  to  eleventh,  J  -J-J  £|;  of 
the  twelfth,  J  J-J  372;  of  the  thirteenth  and  penult,  J  J-{  3;  \;  of  the  anal, 
u(  °;  3;  I'  o-  Coxae  of  anal  legs  armed  laterally  with  a  small  pale  spine. 

Length  (d71)  6.5  mm.;  anal  leg  2.4  mm.  long;  antenna  1.6  mm.  long. 

The  praematurus  form  described  is  from  West  Cliff,  Col.  It  is  the 
specimen  referred  by  Bollman  to  L.  kochii  Stuxberg,  and  is  thus  the 
type  of  color  adcnsis,  the  name  having  been  proposed  on  the  basis  of  a 
difference  indicated  by  Bollman  between  this  specimen  and  typical 
kochii. 

TYPE  LOCALITY.— Colorado:   West  Cliff,  T.  D.  A.  Cockerell. 

Taken  also  in  Colorado  at  Salina  and  Tolland  (T.  D.  A.  Cockerell), 
Durango  (C.  F.  Baker),  Manitou  and  Colorado  Springs. 


NADABIUS  MESECHINUS  (Chamberlin). 
Plate  6,  fig.  2. 

Lithobius  rnesechinus  Chamberlin,  Proc.  Acad.  nat.  sci.  Phil.,  1903,  55,  p.  158. 

DESCRIPTION. —  Brown.  Head  the  same  or  but  little  darker,  the 
anterior  portion  of  frontal  region  pale.  Antennae  pale  brown  or 
yellowish.  Prosternum  like  head,  the  prehensors  lighter.  Venter 
pale  brown,  the  posterior  plates  darker.  Legs  pale  brown  or  testa- 
ceous, the  caudal  pairs  darker. 

Body  robust,  in  types  from  slightly  less  than  6  to  6.4  times  longer 
than  width  of  tenth  plate. 

Head  considerably  wider  than  long  (40  : 37) ;  widest  caudally, 
narrowing  slightly  to  eyes  and  then  very  strongly  cephalad.  Marginal 
breaks  not  conspicuous. 

Antennae  short  as  usual;    composed  of  nineteen  to  twenty -one 


330  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

articles  of  which  the  second  is  considerably  longest  and  those  distad 
of  this  short  and  nearly  uniform,  subcylindric. 

Ocelli  thirteen  to  sixteen  in  three  series:  e.g.,  1  +  5,  4, 3;  1  +  6,  5,  4. 
Single  ocellus  much  largest.  Others  decreasing  in  size  cephalad  and 
ventrad;  compactly  aggregated. 

Prosternum  1.7  times  wider  than  long.  Distance  between  chitinous 
spots  2.2  times  width  at  level  of  bottom  of  sinus;  4.6  times  length  of 
the  short  dental  line.  Teeth  2 +'2;  very  small,  acute;  inner  larger 
than  the  outer.  Spine  small  extending  obliquely  a  little  mesad  of 
directly  cephalad.  Sinus  rather  large,  strictly  v-shaped.  Sides 
ectad  of  spines  broadly  and  widely  rounded. 

First  dorsal  plate  with  sides  moderately  convex  anteriorly  and  at 
caudal  corners,  but  only  little  curved  between  these  parts,  a  little  con- 
verging caudad;  about  two  times  wider  than  long.  Caudal  margin 
of  ninth  plate  straight  or  slightly  extended  at  ends.  Posterior  angles 
of  eleventh  and  thirteenth  dorsal  plates  weakly  produced.  More 
caudal  plates  very  finely  roughened. 

Coxal  pores  of  medium  size  or  large,  circular  or  a  little  transversely 
elongate:  3,4,4,3. 

Spines  of  first  legs,  (HHrB  or  0.0. i. \\m  >  of  the  second,  otorIB  or 
tUH;  of  the  third  to  eighth,  Jj$-JS;  of  the  ninth,  iJJ|J; 
of  the  tenth,  orHrlri;  of  the  twelfth  to  penult,  £  J H; ];  1  the  penult  with 
two  claws;  of  the  anal,  orl~H>  c^aw  one-  Last  two  pairs  of  coxae 
laterally  armed. 

Claw  of  female  gonopods  short;  tripartite;  the  lobes  short,  with 
the  median  one  longest  though  not  much  so.  Spines  unusually  short, 
wide;  sides  parallel  from  base  to  about  middle  of  length  at  which  the 
acutely  acuminate  apical  division  begins;  inner  spine  somewhat 
smaller  than  the  outer.  Inner  side  of  first  article  somewhat  convex. 

Length  8-10  mm.  A  male  10  mm.  long  has  antennae  and  anal  legs 
3.5  mm.  long  and  tenth  plate  1.57  mm.  wide. 

TYPE  LOCALITY. —  Oregon:    Meacham,   August,   1902. 

The  male  of  this  species  is  not  known. 


NADABIUS  IOWENSIS  (Meinert). 
Plate  7,  fig.  6;  Plate  8,  fig.  1. 

Lithobim  iowensis  Meinert,  Proc.  Amer.  philos.  soc.,  1886,  23,  p.  177.  Boll- 
man,  Proc.  U.  S.  N.  M.,  1888,  11,  p.  409.  Chamberlin,  Can.  ent.,  1911, 
43,  p.  70,  103.  Gunthorp,  Kans.  univ.  Sci.  bull.,  1913,  7,  p.  165. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  331 

Lithobius  trilobus  Bollman,  Proc.  U.  S.  N.  M.,  1888,  11,  p.  409  ( <?  d"  in  part). 
Lithobius  bilabiatus  Bollman  (nee  Wood),  Proc.  U.  S.  N.  M.,  1887,  10,  p.  256. 
Lithobius  sexdentatus  Kenyon,  Can.  ent.,  1893,  25,  p.  162. 
Lithobius  bruneri  Kenyon,  Can.  ent.,  1893,  25,  p.  162. 

Nadabius  iowensis  Chamberlin,  Bull.  M.  C.  Z.,  1913,  57,  p.  62.     Can.  ent.,  1914, 
46,  p.  302. 

DESCRIPTION. —  Light  yellowish  or  testaceous  brown  to  dark  brown, 
either  uniform  excepting  the  first  plate,  or  with  the  caudal  plates 
somewhat  darker,  the  first  plate  in  specimens  in  full  color  frequently 
clearly  darker  than  the  adjacent  plates,  approaching  the  head  in  color 
and  sometimes  fully  as  dark  as  the  latter.  Head  from  brown  through 
reddish  brown  to  deep  brownish  black  or  solid  black.  Antennae  from  a 
lighter  brown  to  very  deep  brown,  tips  in  the  latter  case  paler.  Pro- 
sternum  and  prehensors  deep  brown.  Venter  yellowish  to  brown  with 
the  most  caudal  plates  always  conspicuously  darker  brown.  Legs 
yellowish  to  light  brown,  the  caudal  pairs  usually  more  or  less  darker. 

Body  varying  from  only  6.66  to  8  times  longer  than  width  of  tenth 
plate.  Widths  of  head  and  of  first,  third,  eighth,  tenth  and  twelfth 
dorsal  plates  to  each  other  about  as  41  : 37  : 40  : 48  : 49  : 46. 

Head  wider  than  long  usually  in  ratio  22:21.  Sides  strongly 
rounded  and  converging  from  lateral  breaks  about  corners  to  straight 
portion  of  caudal  margin.  Smooth  and  shining,  punctae  few.  Hairs 
sparse,  moderate. 

Antennae  very  short,  reaching  usually  only  to  end  of  fifth  segment. 
Articles  twenty  to  twenty-five,  twenty-three  being  not  infrequent; 
subcylindric  or  a  little  clavately  widening;  moderately  short,  with 
the  second  longest  and  the  distal  ones  becoming  very  slender. 

Ocelli  twelve  to  eighteen  in  four  or  five  series:  e.g.,  1  +  4,  4,  4,  3; 
1  +  4,4,  4,  3,1;  1  +  3,  4,  4,  3,  2;  1  +  3,  4,  4,  3,  1;  1  +  4,  4,  3,  3,  3. 

Single  ocellus  subvertically  subelliptic,  rather  small  though  clearly 
larger  than  any  of  the  seriate  ocelli  which  are  comparatively  small  and 
closely  compacted. 

Prosternum  between  1.45  and  1.5  times  wider  than  long.  Distance 
between  chitinous  spots  2.25—  times  width  at  level  of  bottom  of  sinus; 
3.5-3.7  times  the  dental  line.  Teeth  acute,  well  chitinized  and  usually 
dark,  the  innermost  on  each  side  often  considerably  smaller  than  the 
others;  3  +  3  or  4  +  4,  very  rarely  only  2  +  2,  and  in  one  case 
observed  as  6  +  4,  the  two  extra  teeth  on  the  one  side  being  separated 
by  an  interval  from  the  others.  Sinus  wide,  not  acute  at  bottom. 
Spine  stout  at  base,  distally  slender  and  usually  somewhat  curved 
mesad. 


spine  being  sometimes  missing  on  one  side;    of  the  penult,    '     ' 


332  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

First  dorsal  plate  1.7—  times  wider  than  long;  posterior  corners 
well  rounded,  with  the  sides  in  front  of  them  nearly  straight  and  a 
little  diverging  cephalad  to  the  anterior  ends,  in  some  appearing 
almost  parallel.  Plates  smooth  and  shining  or  rarely  obscurely  some- 
what rugose.  Hairs  becoming  more  numerous  and  somewhat  longer 
on  the  more  caudal  plates.  Posterior  corners  of  ninth,  eleventh,  and 
thirteenth  plates  not  at  all  produced,  being  commonly  obliquely 
excised,  with  line  of  excision  making  but  small  angle  with  the  hori- 
zontal. 

Ventral  plate  clothed  with  rather  numerous  short  hairs  which 
become  more  dense  on  the  caudal  plates. 

Coxal  pores  rather  small,  especially  the  most  proximal  ones;  cir- 
cular: 3,4,4,3;  4,4,4,3;  4,4,4,4;  4,5,5,4. 

0  •  t    fi      4-1  0.  0,  2,  2,  1      0.  0,  2,  2,  1      0,  0,  2,  2,  1     0.  0.  2.  2.  1  0,  0,  2,  2,  2 

Spines  of  first  legs,  570,1,2,1,  oro,  1,3,1,  o.  oil,  si  2,  0.0,2,2.1;  or,  orcHHN 
of  second  to  fifth,  J-";  2!  1,1;  of  sixth,  £  jj;  \  \  \  or  £  1  2!  H;  of  seventh  and 
eighth,  |^fti;  of  ninth  to  eleventh,  ottil'.a  or  oftWi  beinS  often 
of  one  formula  on  one  side  and  of  the  other  on  the  opposite;  of  the 
twelfth,  Gj-J-J-J!  or  J  J  JfJ;  of  the  thirteenth,  o.Vo')!'  aN!  2,  the  trochanter 

o'  ITS'  si 

OTTO,  fti  or  ,  claw  one.1'  Last 

three  pairs  of  coxae  laterally  armed. 

Anal  legs  short.  In  the  female  slender.  In  the  male  somewhat 
thicker  than  in  the  female;  the  third,  fourth,  and  fifth  joints  dorsally 
longitudinally  sulcate  as  usual,  especially  so  the  last  two  of  these,  the 
sulcus  on  the  fifth  joint  being  especially  deep  distad;  fifth  joint 
characterized  by  the  usual  low,  flattened  crest  at  the  distal  end; 
the  crest  highest  distally,  pilose  with  moderately  long  hairs  which 
are  curved  at  tips  (Plate  8,  fig.  1). 

Gonopods  of  male  small,  distally  rounded,  with  sides  also  somewhat 
convex  and  the  outer  longer  and  more  oblique  than  the  inner;  distally 
each  gonopod  bearing  three  or  four  long  bristles. 

Claw  of  female  gonopods  of  moderate  size  and  curvature;  usually 
strictly  entire  but  not  infrequently  with  a  dorsal  and  a  ventral  denticle 
weakly  indicated,  the  claw  being  evidently  entire  in  a  secondary  way; 
acutely  narrowing  distad  but  apex  usually  narrowly  rounded.  Spines 
2  +  2,  or,  occasionally,  3  +  3;  of  moderate  length;  when  viewed  at 
right  angles  to  broad  surface  seen  gradually  to  narrow  distad  with 
the  sides  slightly  convex  and  the  apex  narrowly  rounded;  inner  spine 
normally  somewhat  shorter  than  the  outer  but  the  difference  appears 

1  A  small  accessory  claw  was  observed  on  right  leg  in   a  male  from  Watersmeet,  Mich., 
the  claw  of  the  left  leg  being  single  as  usual. 


CHAMBERLIX:    NORTH    AMERICAN    LITHOBIIDAE.  333 

exaggerated  because  of  the  insertion  of  the  inner  spine  farther  proxi- 
mad.  First  joint  not  at  all  excavated  on  mesal  side  proximally. 

Length  12-16  mm.  A  female  12  mm.  long  has  antenna  and  anal 
leg,  exclusive  of  coxa,  4  mm.  long  and  tenth  plate  1.75—  mm.  wide. 
A  female  of  same  length  may,  however,  have  tenth  plate  only  1.5  mm. 
wide.  A  male  12.5  mm.  long- has  tenth  plate  1.75  mm.  wide  while  a 
second  one  13.5  mm.  long  has  this  plate  of  same  width  as  in  preceding. 
(Watersmeet,  Mich.,  chiefly). 

Pseudomatiirus. —  Dorsum  prevailingly  light  brown,  with  first  plate 
either  abruptly  darker  or  not.  Head  darker  brown.  Antennae  light 
brown  to  yellowish.  Prosternum  and  prehensors  similar  to  head  or 
but  little  paler.  Venter  paler  than  dorsum,  darker  caudally  as  usual. 
Legs  yellowish  to  light  brown,  the  posterior  pairs  distally  more  pig- 
mented,  somewhat  light  ferruginous  or  orange. 

Antennae  as  in  matunis. 

Ocelli:  e.g.,  1  +  3,  3,  3,  2;  1  +  4,  3,  3,  1;  1+4,  3,  3,  2;  1  +  4,  4, 
3,  2,  1.  Thus  averaging  fewer  than  in  the  adult  and  more  commonly 
in  four  series. 

Prosternum  with  teeth  3  +  3  or  2  +  2 ;  when  3  +  3  the  innermost 
often  much  smaller  and  close  to  side  of  sinus. 

Coxal  pores  very  small;  most  frequently:  3,  4,  4,  3;  also  3,  3,  3,  3 
to  4,  4,  4,  3. 

Claw  of  female  gonopods  smaller  and  more  acute  and  paler  than  in 
adult.  Spines  essentially  as  in  maturus  but  distally  more  acute  and 
the  inner  one  proportionately  somewhat  smaller.  Bristles  fewer. 

Gonopods  of  male  small  and  rounded;  already  bearing  the  three 
bristles. 

Spines  of  first  legs,  J-  J  J  £  \  to  J-J  |  J };  of  seventh  may  be,  J  J  \  \  \  or 
(HrliJ;  of  anal,  JJiii  or  ttHlJ  others  as  in  maturus.  Last  two 
pairs  of  coxae  laterally  armed  or  last  three  pairs  as  in  maturus. 

Anal  legs  of  male  modified  as  in  the  maturus  but  the  crest  somewhat 
smaller  and  its  hairs  fewer. 

Length  10.5-13  mm.  A  female  11  mm.  long  has  antenna  3.5  mm. 
and  anal  leg  near  3  mm.  long.  (Mongona,  Iowa). 

Pracmaturus . —  Dorsum  yellowish  to  testaceous  and  brown.  Head 
brown,  always  darker  than  dorsum  of  body.  Antennae  light  brown 
proximally,  paler  distally.  Prosternum  and  prehensors  testaceous  to 
brown,  usually  distinctly  darker  than  the  venter  which  is  yellow  to 
dilute  brown,  tenth  caudal  plates  darker  as  usual.  Legs  like  venter, 
but  posterior  pairs  distally  light,  subferruginous  or  orange. 

Antennae  nearly  as  in  older  stages. 


334  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Ocelli  nine  to  fourteen  in  three  to  five  series,  but  mostly  in  three 
or  four:  e.g.,  1  +  3,  3,  2;  1  +  3,  3,  3;  1  +  4,  3,  3,  3;  1  +  4,  3,  3,  2,  1. 
All  ocelli  deeply  pigmented. 

Prosternal  teeth  2  +  2,  equal  or  very  nearly  so,  rather  pale.  Sinus 
wide,  subacute  at  bottom.  1.47  times  wider  than  long.  Distance 
between  chitinous  spots  2.38  times  width  at  sinus,  3.3  times  dental  line. 

Coxal  pores  very  small:  2,3,3,2;  3,3,3,3;  3,4,4,3. 

Claw  of  female  gonopods  small,  entire,  slender  and  acute,  pale. 
Spines  2  +  2,  acutely  acuminate,  the  inner  much  shorter  and  more 
slender  than  the  outer.  Distal  article  mostly  with  but  one  bristle; 
the  second  with  two  or  three;  and  the  first  with  three. 

Spines  of  first  legs,  570! ill  or  orororll;  °f  tne  second  and  third, 
eHHrl'i  or  1HHHH;  of  the  fourth  to  seventh,  JJUl;  of  the  eighth, 
(HHHH;  of  the  ninth  to  eleventh,  JJJfl;  of  the  twelfth,  o.oilrl;  of 
the  thirteenth,  ^J-J-J-J;  of  the  penult,  J  J  J  J  jj;  of  the  anal,  HHrH  or 
off^Hfi  Only  the  last  pair  of  coxae  laterally  armed. 

Length  9.5-11  mm.  A  female  10.5  mm.  long  has  antenna  4  mm. 
and  anal  leg  3+  mm.  long  and  tenth  plate  1.3  mm.  wide.  The  maxi- 
mum length  overlaps  the  minimum  for  the  pseudomaturus.  (Mon- 
gona,  la.) 

Immaturus. —  Dorsum  pale  brown,  most  plates  showing  three  paler 
longitudinal  lines,  of  violaceous  tinge  throughout.  Head  and  posterior 
plates  darker.  Prosternum  and  prehensors  similar  to  head.  Antennae 
light  brown,  paler  distally.  Venter  and  legs  pale,  the  posterior  pairs 
usually  more  brightly  pigmented. 

Antennae  in  most  composed  of  nineteen  articles  of  which  those 
distad  of  the  third  are  mostly  very  short,  though  varying  considerably 
in  length,  as  usual  in  yet  developing  antennae. 

Ocelli  seven  to  ten  in  two  or  three  series:  e.g.,  1  +  4,  2;  1  +  3,  3; 
1  +  3,  3,  2;  1  +  4,  3,  2.  First  ocellus  of  top  series  as  large  as  or 
larger  than  the  single  ocellus. 

Prosternal  teeth  2  +  2,  equal,  pale.  Sinus  somewhat  more  acute 
at  bottom  than  in  maturus. 

Coxal  pores  very  small,  the  most  proximal  one  on  each  coxa  espe- 
cially minute:  2,  2,  2,  2;  2,  3,  3,  2. 

In  the  smaller  specimens  short  and  pale  but  the  three  articles  al- 
ready present;  of  these  the  distal  is  short  and  simply  rounded  with  no 
indication  of  a  claw  and  is  glabrous;  second  article  with  one  bristle 
and  first  one  with  one  longer  bristle  in  addition  to  the  minute  pale 
chitinous  point  representing  the  spine;  sternite  with  two  bristles. 
In  larger  specimens  the  claw  is  present,  being  small,  slender,  and  acute; 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  335 

distal  article  with  one  bristle,  second  mostly  two  and  first  usually  four 
while  sternite  may  bear  as  many  as  ten. 

Spinesof  first  legs,|WJto  M^1;  of  the  second,^;!  to  j$Hi; 
of  the  third,  $n$  to  K&H;  of  the  fourth  and  fifth,  mffi  to 
tti-H  and  JJJ  J  J;  of  the  sixth,  StoVorH  to  ^|22;  of  the  seventh  to 
ninth,  tJi-H  to  JJill;  of  the  tenth,  JJj;|*,  j&JK  to  JJJ-K;  of 
the  eleventh,  fc  J-&-J  or  JU{|;  of  the  twelfth,  jftJH  to  frHSl;  of 
the  thirteenth,  £  ffj  J  or  57170!  1;  of  the  penult,  fSf^j  of  the  anal, 
orHrHto  Hrl i ;  i-  Last  pair  of  coxae  alone  laterally  armed. 

Length  5.6-9  mm.  In  specimen  5.6  mm.  long  widths  of  head  and 
of  first,  third,  eighth,  tenth  and  twelfth  plates  are  to  each  other  as 
20.5  : 18.5  :  20  :  23  :  24  :  22.  (Earliest  stage,  Watersmeet,  Mich.; 
later,  Mongona,  Iowa.)  * 

TYPE  LOCALITY. —  Iowa:   McGregor. 

Found  also  in  Iowa  at  McGregor  (Davis),  Mongona,  Tama,  Boone, 
De  Witt.  Nebraska:  Omaha,  Fremont.  Kansas:  Anderson, 
Bourbon,  Coffey,  Cowley,  Douglas,  Franklin,  Graham,  Jefferson, 
Labette,  Linn,  Pottawatomie,  Reno,  Sumner,  and  Trego  counties 
(fide  Gunthorp).  Illinois:  Rock  Island,  Franklin  Grove,  Sterling, 
Peoria,  East  Peoria.  Indiana:  Bloomington  (Bollman  coll.),  La 
Fayette,  Richmond,  Greencastle,  Salem,  New  Providence,  Wyandotte 
(fide  Bollman).  Michigan:  Watersmeet,  Saunders,  Menominee, 
Ludington.  Wisconsin:  Beloit,  Haugen,  Marinette.  Colorado: 
Manitou  (Hayden  Exp.  1873,  Camp).  Wyoming:  Cheyenne. 

Variation  in  this  species  from  place  to  place  is  large,  the  place- 
modes  for  size  and  other  characters  often  differing  considerably.  In 
some  places  the  ventral  spines  of  the  anal  legs  would  seem  to  be  the 
more  frequently  1,  3,  2,  1  (some  places  in  Illinois  and  Wisconsin) 
whereas  in  others  the  formula  is  almost  exclusively  1,  3,  3, 1.  Segrega- 
tion of  a  distinct  local  variety,  however,  seems  nowhere  to  have  been 
clearly  effected.  Specimens  cannot  be  referred  to  the  different  stages 
of  postembryonal  development  on  the  basis  of  size  because  of  frequent 
and  wide  overlapping.  The  range  in  size  of  the  immaturus,  as  limited 
in  the  usual  way,  is  very  large  as  it  is  also,  e.g.,  in  the  spining  of  the 
legs  as  noted  above. 

An  examination  of  specimens  in  several  vials  from  Bloomington, 
Ind.,  (Coll.  U.  S.  N.  M.)  labeled  by  Bollman  as  L.  trilobus  shows  them 
for  the  most  part  to  be  referable  to  the  present  species,  some  speci- 
mens, however,  are  T.  pullus.  As  these  specimens  do  not  very  well 
conform  to  the  original  description,  it  may  be  supposed  either  that 
they  were  incorrectly  referred  or  that  there  has  been  a  transfer  of 


336  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

labels  or  an  incorrect  reference  by  number,  as  many  of  Mr.  Bollman's 
specimens  were  indicated  only  by  numbers  referring  to  his  personal 
catalogue. 

NADABIUS  EIGENMANNI  (Bollman). 

Plate  7,  fig.  5. 
Lithobius  eigenmanni  Bollman,  Proc.  TJ.  S.  N.  M.,  1888,  10,  p.  625.. 

DESCRIPTION. —  Dorsum  testaceous  to  brown.  Head  in  long 
preserved  specimens  seems  also  to  be  brown  with  frontal  region  paler, 
of  orange  tinge.  Antennae  yellowish,  darker  proximally.  Proster- 
num  like  head,  or  a  little  paler.  Venter  pale,  yellowish  or  testaceous, 
with  the  caudal  platv,  more  deeply  pigmented  as  usual,  brown  of 
orange  tinge.  Most  legs  pale,  the  posterior  pairs  bright  yellow  or 
orange. 

Body  from  7.25  (in  type  specimen)  to  7.75  or  8  times  longer  than 
width  of  tenth  plate,  being  a  robust  form.  Widths  of  head  and  of 
first,  third,  eighth,  tenth,  and  twelfth  plates  to  each  other  about  as 
28  :  26  :  27  :  31  :  32  :  30.5  to  considerably  wider. 

Head  from  equal  in  length  and  breadth;  of  usual  general  shape; 
caudal  margin  weakly  and  widely  incurved. 

Antennae  short ;  articles  short  and  of  usual  arrangement.    Hairs  long. 

Each  eye  consisting  of  from  eight  to  eighteen  ocelli  arranged  in 
two  or  three  to  four  and  occasionally  five  series:  e.g.,  1  +  4,  3; 
1  +  4,  4,  3,  1  +  4,  3,  3;  1  +  4,  3,  1;  1  +  4,  3,  2;  1  +  4,  4,  3,  1; 
1  +  4,  4,  4,  3;  1  +  3,  4,  5,  4,  1.  Single  ocellus  often  small,  those  of 
most  dorsal  row,  or  at  least  most  caudal  one,  the  largest  of  all,  as  well 
as  most  caudal  of  second  row,  commonly  exceeding  it  in  size;  or,  in 
largest  specimens,  the  single  ocellus  is  distinctly  largest.  Ocelli  com- 
monly not  crowded,  deeply  pigmented,  and  rather  irregular  in  form 
and  size. 

Prosternum  1.5  (type)  or  mostly  near  1.6  times  wider  than  long. 
Distance  between  chitinous  spots  2.4,  or  a  little  less,  times  the  width 
at  level  of  bottom  of  sinus;  3.5  to  3.8+  times  the  dental  line.  Mesal 
,  incision  of  moderate  width,  its  sides  recurved.  Teeth  equal  in  size 
or  nearly  so,  rather  small,  line  of  apices  a  little  recurved.  Spine  not 
very  close  to  tooth;  much  stouter  at  base  than  the  bristles,  narrowing 
rapidly  distad  and  above  level  of  apex  of  tooth  slender  and  bristle-like. 

First  dorsal  plate  1.8  times  wider  than  long;  sides  strongly  diverg- 
ing cephalad.  Dorsal  plates  rather  strongly  arched.  Smooth. 
Posterior  inner  plates  with  corners  obliquely  truncate. 


CHAMBERLIX:   NORTH   AMERICAN    LITHOBIIDAE.  337 

Coxal  pores  circular:  2,3,3,2;  2,3,3,3;  2,4,4,3;  3,4,4,  3; 
4,  5,  5,  5. 

Spines  of  first  legs,  Kvxi  and  o! o, i'. I'. i  (pseudomaturus)  to  JJ-|-Ji 
and  ^ojij',2  (maturus);  of  the  second,  oioHuxi  an(i  o!  o!  i!  si  1  (pseudomat- 
urus),  to  oHHH  and  J |||;|;  of  the  third  to  sixth,  £ oforl  J o. Hri  or 
(ro't  a  2  in  fully  grown  specimens;  of  the  seventh  to  eleventh,  o' o'firf  or 
fttfe  of  the  twelfth,  fc-ftJJ,  JJ-JJJ  or  «;K||,  the  coxa  rarely 
armed;  of  the  thirteenth,  JJJU  or  JtiHHH;  of  the  penult,  HfH 
claws  three;  of  the  anal,  olij^'o,  with  the  claw  single.  Last  two 
pairs  of  coxae  laterally  armed. 

Anal  legs  in  male  considerably  inflated,  the  fourth  joint  most 
noticeably  so.  Third,  fourth,  and  fifth  joints  longitudinally  fur- 
rowed above,  the  fourth  the  most  distinctly  ^o.  Fourth  joint  on 
mesodorsal  side  toward  distal  end  subdensely  clothed  with  long  hairs 
which  at  the  tips  are  curved  somewhat  caudad;  joint  elsewhere  only 
sparsely  clothed  with  short  hairs ;  fifth  joint  at  distal  end  above  with 
the  usual  crest  which  is  low  and  often  inconspicuous  excepting  in 
fully  grown  specimens.  Penult  legs  a  little  less  inflated;  similarly 
sulcate;  the  fourth  joint  without  the  special  growth  of  hair. 

Gonopods  of  male  with  outer  side  more  oblique  than  the  mesal; 
distally  transversely  straight  or  nearly  so;  thin,  edge-like,  distad. 

Claw  of  female  gonopods  short  and  proportionately  wide;  tripar- 
tite, with  the  median  lobe  little  longest  and  the  outer  often  somewhat 
smaller  than  the  inner.  Basal  spines  short  and  very  broad,  with  sides 
subparallel  or  somewhat  diverging  distad  to  the  acuminate  apical 
portion  which  is  rather  short  and  acute  with  its  sides  more  or  less 
incurved;  inner  spine  considerably  and  constantly  smaller  than  the 
outer  (Plate  7,  fig.  5).  Mesal  edge  of  first  article  straight,  as  usual 
in  the  genus. 

Length  from  7  to  12.5  mm.  A  male  9  mm.  long  has  antennae 
3.25  mm.  and  anal  leg  3  mm.  long  with  tenth  plate  1.17  mm.  wide. 

TYPE  LOCALITY. —  British  Columbia:   Glacier  (C.  H.  Eigenmann). 

Taken  also  in  British  Columbia  at  Kaslo.  Oregon:  Portland, 
August,  1902. 

The  description  above  is  based  in  part  upon  the  types  of  the  species; 
but  these  are  not  fully  developed  and  are  in  bad  condition  so  that 
some  features  could  not  be  made  out  with  certainty.  The  main  part 
of  the  account  was  consequently  drawn  from  specimens  collected  at 
Portland,  Oregon,  and  Kaslo,  B.  C. 

The  species  in  the  region  about  Kaslo  varies  much,  but  intergrades 
seem  too  frequent  for  the  separation  of  a  distinct  variety. 


338  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


NADABIUS  HOLZINGERI  (Bollman). 

Lithobius  holzingeri  Bollman,  Entomol.  Amer.,  1887,  3,  p.  83.     Chamberlin, 
Can.'  ent.,  1911,  43,  p.  104. 

DESCRIPTION. —  Brown  to  chestnut,  the  head  darker.  Prosternum 
nearly  like  head,  the  prehensors  somewhat  paler.  Venter  paler 
brown,  the  caudal  plates  darker,  somewhat  chestnut.  Legs  yellowish 
brown  or  brown,  the  caudal  pairs,  as  usual,  clearly  darker. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  44  :  44  :  45  :  52  :  54  :  52. 

Head  wider  than  long  in  ratio  22  : 19.  Widest  at  marginal  breaks, 
which  are  pronounced.  Caudal  margin  straight.  A  transverse 
impression  a  little  in  front  of  caudal  marginal  thickening,  the  impres- 
sion deepest  at  middle. 

Antennae  short.  Articles  twenty  to  twenty-three  (twenty-eight 
seq.  Bollman);  short. 

Ocelli,  in  types  examined,  sixteen  or  seventeen  in  four  or  five  series : 
e.  g.,  1  +  4,  4,  4,  3;  1  •+  3,  4,  4,  4;  1  +  3,  4,  3,  3,  3.  Single  ocellus 
elliptic  or  oval,  large. 

Prosternum  1.5  or  1.6  times  wider  than  long.  Distance  between 
chitinous  spots  2.25-2.5  times  the  width  at  level  of  bottom  of  sinus; 
3.4—3.5  times  length  of  dental  line. 

First  dorsal  plate  with  sides  rounded  and  diverging  cephalad;  1.76 
times  wider  than  long.  Posterior  angles  of  eleventh  and  thirteenth 
dorsal  plates  with  a  slight  tendency  toward  production  as  usual. 

Coxal  pores  circular,  moderately  small:  3,  4,  4,  4;  4,  5,  5,  4; 
5,  6,  6,  5. 

Spines  of  first  legs,  oTrlrH;  of  the  second  to  fourth,  SHJ'-ffl;  of  the 
fifth  to  tenth,  JHirtfl;  of  the  eleventh  and  twelfth,  tSfJi;  of  the 
thirteenth,  oriKl;  of  the  penult,  orJJJik  claws  three,  the  two  acces- 
sory claws  being  large  and  distinct;  of  the  anal,  K|~KHI»  claw  one>  long- 
Last  pair  of  coxae  laterally  armed. 

Anal  legs  of  male  short  and  moderately  thickened;  fourth  and  fifth 
articles  dorsally  rather  strongly  longitudinally  sulcate  and  the  fifth 
joint  having  at  its  distal  end  a  low,  thin  crest  in  usual  position,  with 
its  dorsal  line  convex  and  highest  distad.  Penult  legs  similarly  some- 
what thickened  and  dorsally  furrowed,  but  with  no  crest. 

Gonopod  of  male  subcuneate,  distally  sub  truncate;  bearing  three 
bristles. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  339 

Claw  of  female  gonopods  short,  wide,  tripartite.  Spines  short  and 
stout,  subequal. 

Length  10  to  14  mm.  A  male  14  mm.  long  has  antenna  5.5  and 
anal  leg  near  4.5  mm.  long. 

TYPE  LOCALITY. —  Minnesota:    Winona.     (J.  M.  Holzinger). 

The  description  above  is  drawn  from  three  of  the  original  types 
(c?  cf1),  the  statement  as  to  the  female  gonopods,  however,  being  taken 
from  the  original  description.  Bollman  gives  length  of  males  as  from 
16  to  21  mm.,  but  this  is  much  too  large  as  is  frequent  with  Bollman's 
measurements, —  possibly  the  anal  legs  are  included  in  them. 

POKABIUS  Chamberlin. 

Poabius  Chamberlin  (nee  Koch),  Ann.  Ent.  soc.  Amer.,  1912,  6,  p.  153. 
Pokabius  Chamberlin,  Can.  ent.,  1912,  44,  p.  316. 

Head  with  lateral  marginal  interruptions  distinct  (Pokabius  sens, 
sir.;  Anobius)  or  sometimes  scarcely  evident  (Lophobius). 

Antennae  short  or  very  short;  articles  normally  twenty,  occasion- 
ally varying  a  little  from  this  in  individual  cases. 

Eye  composed  of  seriate  ocelli  which  are  from  six  to  twenty-five  in 
number  and  are  arranged  in  from  two  to  six  series.  Single  ocellus 
enlarged. 

Prosternal  teeth  2  +  2;  line  of  apices  more  or  less  recurved.  Spines 
slender,  distally  bristle-like. 

Posterior  angles  of  none  of  the  dorsal  plates  or  those  of  the  ninth, 
eleventh,  and  thirteenth  produced. 

Coxal  pores  uniseriate,  circular. 

Gonopods  of  the  male  uniarticulate. 

Claw  of  female  gonopods  normally  tripartite,  occasionally  only 
bipartite,  the  median  lobe  commonly  not  much  longest.  Basal  spines 
2  +  2,  usually  intermediate  in  length  and  stoutness,  but  varying  in 
both  directions.  First  article  of  gonopods  not  excavated  proximally. 

Tarsi  of  all  legs  divided. 

Anal  legs  of  the  male  with  fourth  joint  characterized  by  a  dorsal 
longitudinal  ridge  more  or  less  conspicuously  elevated  into  a  lobe  at 
or  near  the  proximal  end,  and  the  third  joint  with  a  dorsal  ridge  usually 
elevated  at  the  distal  end  (Pokabius  sens,  sir.;  Anobius,  Plate  8,  fig.  4; 
Plate  9,  fig.  1,  3,  4;  Plate  10,  fig.  1,  3;  and  Plate  11,  fig.  1,  2);  or  in 
some  species  the  ridge  of  fourth  joint  less  developed  and  more  or  less 
elevated  at  distal  end  or  in  some  cases  practically  absent  (Lophobius). 
Penult  legs  never  with  any  special  lobes  (excepting  in  P.  (Anobius) 
centurio). 


340  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


n 


FIG.  8.— Distribution  of  Pokabius. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  341 

From  one  to  three  last  pairs,  or  rarely  none,  of  coxae  laterally  armed. 
Fifth  joint  of  all  legs  between  first  and  twelfth  with  two  dorsal  spines. 
Dorsal  spines  of  anal  legs  in  female  varying  from  1,  0,  2,  1,  0  and 
1,  0,  3,  1,  0,  the  most  common  formula,  to  1,  0,  4,  1,0,  and  in  the  male 
from  1,  0,  2,  1,  0  to  1,  0,  6,  1,  0;  ventral  0,  1,  3,  2,  0  or  0,  1,  3,  2,  1; 
claw  one  (or  in  socius  only).  Dorsal  spines  of  penult  legs  1,  0,  3,  1,  1 
or  rarely  1,0,  2, 1,1;  ventral,  0, 0,  2,  3,  2  to  0, 1,3,3, 1  andO,  1,  3,  3,  2; 
claws  two  or  three.  Dorsal  spines  of  thirteenth  legs  1,  0,  3,  1,  1  or 
rarely  (utahensis}  1,  0,  2,  1,  1;  ventral,  0,  1,  3,  3,  2  or  0,  0,  3,  3,  2, 
rarely  only  0,  0,  2,  3,  1  (utahensis}.  Dorsal  spines  of  twelfth  legs 
1,  0,  3,  1,  1  or  rarely  1,  0,  2,  1,  1  to  1,  0,  3,  1,  2;  ventral  0,  0,  2,  3,  2  or 
0,  0,  3,  3,  2.  Dorsal  spines  of  first  legs,  0,  0,  2,  2,  1  to  0,  0,  3,2,2; 
ventral  0,  0,  1,  2,  1  to  0,  0,  2,  3,  2. 

Length  6.5  to  17.5  mm.  but  mostly  from  9  to  15  mm. 

TYPE. —  P.  vcrdescens  Chamberlin. 

Variation  among  the  species  embraced  in  the  genus  as  here  defined 
is  in  many  features  large;  but  there  seems  no  reason  to  doubt  its 
entire  naturalness  excepting  only  the  portion  designated  as  the  sub- 
genus  Lophobius.  The  latter  may  have  to  be  withdrawn  and  possibly 
subdivided  when  the  region  over  which  it  ranges  is  more  thoroughly 
explored  and  the  species  now  recognized  and  others  yet  to  be  found  are 
better  known  in  both  sexes. 

Pokabius  is  a  comparatively  large  genus  having  its  center  in  the 
southwest,  ranging  up  the  west  coast  to  Washington  and  British 
Columbia  and  up  the  Mississippi  valley  to  southern  Minnesota  and 
Wisconsin  (Figure  8).  In  the  upper  Mississippi  valley  it  is  represented 
chiefly  by  P.  bilabiatus  a  very  abundant  species.  The  distribution 
of  the  subgenus  Lophobius  is  separately  shown  (Figure  9).  The 
species  of  Lophobius  are  found  under  stones  over  foothills  and  in 
similar  open,  dryer  and  less  wooded  areas  in  largely  semi-desert 
regions. 

The  key  does  not  include  P.  carinipes  (Daday),  which  is  insuffi- 
ciently known.  (Cf.  p.  367). 

Key  to  Subgenera  and  Species  of  Pokabius. 

a.     Posterior  angles  of  ninth,  eleventh,  and  thirteenth  dorsal  plates 

produced Anobius,  subgen.  nov.1 

b.  Dorsal  spines  of  twelfth  legs  1(0),  0,  3,  1,  2;  head  wider  than 
long;  penult  leg  of  c?  with  a  lobe  on  the  fourth  joint;  length 
10  mm.  or  less P.  centurio  (Chamberlin). 

1  P.  (Anobius)  centurio  (Chamberlin).     TYPE. 


342  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

bb.     Dorsal  spines  of  twelfth  legs  1,  0,  3,  1,  1 ;  head  as  long  as  wide; 
penult  leg  in  cf  with  no  such  lobe;   length  13-16  mm. 

P.  gilae,  sp.  nov. 
aa.     Posterior  angles  of  none  of  the  dorsal  plates  produced. 

b.     Anal  leg  of  d"  with  a  dorsal  ridge  on  fourth  joint  elevated  into 
a  conspicuous  lobe  at  or  near  the  proximal  end;    marginal 

interruptions  of  head  conspicuous Pokabius  sens.  sir. 

c.     Dorsal  spines  of  anal  legs  of  cf  1,  0,  4,  1,  0  to  1,  0,  6,  1,0; 

of  9  .     1,  0,  4,  1,  0. 

d.     Body  8.75-9.5  times  longer  than  width  of  tenth  plate; 
ventral  spines  of  thirteenth  legs  usually  0,  1,  3,  3,  2. 

P.  bilabiatus  (Wood). 

dd.     Body  only  6.7-8  times  longer  than  width  of  tenth  plate; 
ventral  spines  of  thirteenth  legs  usually  0,  0,  3,  3,  2. 

P.  bilabiatus  verdescens  Chamberlin. 
cc.     Dorsal  spines  of  anal  legs  1,  0,  3,  1,  0  or  1,  0,  2,  1,  0  in  both 

cf  and  9  . 
d.     None  of  the  coxae  laterally  armed.     Ventral  spines  of 

penult  legs  0,  1,  3,  3,  1 P.  disantus,  sp.  nov. 

dd.     One  or  more  pairs  of  posterior  coxae  laterally  armed; 

ventral  spines  of  penult  legs  0,  1,  3,  3,  2. 
e.     Only  the  last  pair  of  coxae  laterally  armed. 
/.     Distance  between  chitinous  spots  3.5  times  the  dental 
line  and  near  2.33  times  width  at  sinus;  anal  leg  of 

cf  (Plate  10,  fig.  3) P.  utahcnsis  (Chamberlin). 

ff.  Distance  between  chitinous  spots  near  4.4  times 
dental  line  and  2.9  times  width  at  sinus;  anal  leg  of 

cf  (Plate  11,  fig.  2) P.  sokomis  (Chamberlin). 

ee.     Last  2  or  3  pairs  of  coxae  laterally  armed. 

/.  Anal  legs  of  cf  with  dorsal  spines  normally  1,  0,  2,  1,0 
and  lobe  of  fourth  joint  at  extreme  proximal  end 

(Plate  9,  fig.  1) P.  clavigcrens  (Chamberlin). 

//.  Anal  leg  of  both  d"  and  9  with  dorsal  spines  1, 0, 3, 1, 0 
and  lobe  of  fourth  joint  cephalad  of  extreme  proxi- 
mal end. 

g.     Dorsal  spines  of  first  legs  normally  0,0,3,2,2; 

claw  of  9  gonopods  subtruncate  with  lobes  but 

weakly  indicated;  anal  leg  of  cf  (Plate  9,  fig.  4). 

P.  pitophilus  (Chamberlin). 

gg.     Dorsal   spines  of  first  legs  normally  0,  0,  2,  2,  2 ; 
claw  of  9   gonopods  distally  acute  with  3  lobes 


CHAMBERLIN:  ;NORTH  AMERICAN  LITHOBIIDAE.  343 

distinct  and  the  median  much  longest;   anal  leg 

of  cf  (Plate  8,  fig.  4).  .P.  iginus  (Chamberlin). 

bb.     Anal  leg  of  cf  with  dorsal  ridge  elevated,  if  at  all,  at  distal  end, 

never  with  lobe  at  proximal  end,  sometimes  not  evident; 

marginal  interruptions  of  head  usually  weak  or  scarcely 

manifest Lophobius,  subgen.  nov. 

c.     All  of  anterior  legs,  or  all  but  first  1  or  2  pairs,  with  third 

joint  bearing  2  ventral  spines. 
b.     Ventral  spines  of  penult  legs  0,  1,3,  3,  2. 

c.     Anal  leg  with  2  claws P.  socius  (Chamberlin). 

cc.     Anal  leg  with  the  claw  single. 

d.     Dorsal  spines  of  twelfth  legs  1,  0,  3,  1,  1. 
e.     Ventral  spines  of  anal  legs  0,  1,  3,  2,  0;    of  the  twelfth 
and  thirteenth  0,  0,  3,  3,  2. 

P.  collium  (Chamberlin). 

ee.     Ventral  spines  of  anal  legs  0,  1,  3,  2,  1;   of  twelfth  and 
thirteenth,  0,0,2,3,2.  .P.pungonius  (Chamberlin). 
dd.     Dorsal  spines  of  twelfth  legs  1,  0,  3,  2,  2  or  1,  0,  3,  1,  2. 
e.     Ventral  spines  of  anal  legs  0,1,3,2,1;    head  a  little 

longer  than  wide P.  arizonae,  sp.  nov. 

ee.    Ventral  spines  of  anal  legs  normally  0,  1,  3,  2,  0;   head 

wider  than  long P.  helenae,  sp.  nov. 

bb.     Ventral  spines  of  penult  legs  0,  1,  3,  3,  1  (lobe  at  distal  end  of 
fourth  joint  of  anal  leg  in  d*  strongly  developed). 

P.  castellopcs  (Chamberlin). 

aa.     First  7  pairs  of  legs  with  the  third  joint  bearing  but  a  single 
ventral  spine P.  eremus,  sp.  nov. 


ANOBIUS,  subgen.  nov. 
POKABIUS  CENTURIO  (Chamberlin). 
Plate  10,  fig.  1,  2. 

Lithobius  centurio  Chamberlin,  Proc.  Acad.  nat.  sci.  Phil.,  1905,  56,  p.  651. 
Poabius  nankus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  5,  p.  153,  pi.  12,  fig.  4. 

DESCRIPTION. —  From  light  orange-brown  to  dark  brown  in  speci- 
mens in  full  color;  with  typically  a  darker  median  longitudinal  band 
more  or  less  evident,  and  with  some  of  the  major  plates  in  some  degree 
darkened  along  caudal  border.  Head  nearly  same  as  dorsum  or  a 
little  lighter,  paler  in  front  of  suture  and  darkened  over  middle  of 


344  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

caudal  portion.  Antennae  light  brown.  Venter  a  lighter  brown 
than  dorsum,  the  posterior  sternites  darkest,  all  excepting  the  latter 
with  a  paler  central  circular  area.  Anterior  legs  yellowish,  the  pos- 
terior pairs  becoming  brown,  uniform. 

Body  very  robust,  being  typically  only  about  5.5  times  longer  than 
width  of  tenth  plate.  Twelfth  plate  as  wide  as,  or  wider  than,  the 
tenth,  and  the  tenth  wider  than  the  eighth.  Widths  of  head  and  of 
first,  third,  eighth,  tenth,  and  twelfth  plates  to  each  other  as  49  :  46  : 
51  :  61  :  68  :  70. 

Head  considerably  wider  than  long  (about  10  :  9).  Caudal  margin 
widely  and  moderately  incurved.  Width  not  much  varying  in  region 
between  eyes  and  a  level  a  little  caudad  of  marginal  breaks,  which  are 
weak  and  very  oblique,  the  sides  caudad  of  this  region  strongly  con- 
verging to  caudal  corners.  A  deep  and  conspicuous  but  rather  short 
transverse  sulcus  parallel  with  and  a  little  in  front  of  median  portion 
of  frontal  suture.  A  shallow  curving  longitudinal  furrow  each  side  of 
middle  in  front  of  caudal  border.  Finely  punctate  and  but  slightly 
weakly  roughened. 

Antennae  short;  articles  normally  twenty  but  varying  from  nine- 
teen to  twenty-two,  moderate,  decreasing  distad. 

Ocelli  fifteen  to  twenty-two  in  usually  four  series:  e.  g.,  1  +  5, 
4,  4,  1;  1  +  5,  4,  4,  2;  1  +  5,  5,  4,  3;  1  +  6,  6,  5,  4.  Ocelli  closely 
curved  and  in  consequence  commonly  hexagonal.  Single  ocellus 
large,  elliptic,  lying  obliquely  beneath  and  contiguous  with  caudal 
ends  of  series. 

Prosternum  about  1.6  times  as  wide  as  long.  Width  between  chitin- 
ous  spots  2.75,  or  somewhat  more,  times  as  great  as  width  at  level  of 
bottom  of  sinus;  5.2  times  as  great  as  dental  line.  Teeth  2  +  2; 
small,  acute,  with  apical  portion  sometimes  extended  into  a  bristle- 
like  tip  which  is  easily  broken  off.  Spine  as  usual,  distally  bristle-like, 
borne  on  a  small  tubercle  ectad  of  outer  tooth,  about  three  somewhat 
similar  bristles  ectad  of  the  spine. 

All  dorsal  plates  finely  roughened  but  the  caudal  ones  more  dis- 
tinctly so.  Most  plates  with  a  median  furrow,  sometimes  replaced 
by  two,  and  on  each  side  one  or  two  approximate  ones  diverging  from  it 
caudad.  Ninth,  eleventh,  and  thirteenth  dorsal  plates  with  the  caudal 
angles  strongly  produced,  but  apices  of  processes  a  little  rounded  rather 
than  acute.  Posterior  angles  of  seventh  plate  very  slightly  extended 
caudad,  the  mesal  side  of  extended  portion  long  and  making  but 
slight  angle  with  median  portion  of  the  margin.  Caudal  corners  of 
sixth  plate  a  little  obliquely  excised.  Lateral  and  caudal  margins  of 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  345 

plates  bearing  numerous  very  short,  acutely  tipped,  hairs  upon  minute 
serratures. 

Ventral  plates  with  two  main  wide  transverse  furrows  between 
which  there  may  be  finer  impressed  lines.  The  last  plate  with  two 
sharply  impressed  longitudinal  sulci  converging  from  the  anterior 
margin  and  ending  abruptly  at  about  middle  of  the  plate,  where  their 
ends  are  united  by  a  less  strongly  impressed  transverse  sulcus;  the 
preceding  plate  similarly  but  rather  less  conspicuously  marked.  Last 
ventral  plate  with  adjacent  coxae  and  succeeding  segment  subdensely 
pilose,  the  anterior  plates  being  only  very  sparsely  clothed. 

Coxal  pores  small  and  circular,  with  those  of  each  coxa  widely 
separated:  2,3,3,2;  3,3,3,3. 

Spines  of  the  first  legs,  o  o  i"3  2!  of  the  second  to  tenth,  o'o'^'H; 
of  the  eleventh,  JSK  2!  of  the  twelfth,  ^b^AV ;  of  the  thirteenth, 
or i!  l',%, 2!  of  the  penult  same  as  of  thirteenth,  claws  three;  of  the  anal, 
MJii  (c?)  or  J;ivH  (9,  also  cf),  claw  one.  Last  pair  of  coxae 
laterally  armed. 

Anal  legs  of  male  short  and  rather  slender;  the  third  joint  abruptly 
produced  at  extreme  distal  end  subdorsally  into  a  high  lobe,  the  caudal 
face  of  which  is  vertical  or  at  right  angles  to  axis  of  joint  and  the 
anterior  face  but  little  slanting,  the  lobe  bearing  two  (or  one)  of  the 
dorsal  spines;  fourth  joint  produced  into  a  larger  conspicuous  lobe  at 
proximal  end  and  contiguous  with  the  lobe  of  the  preceding  joint,  the 
lobe  somewhat  plate-like,  continuing  caudad  as  a  lower  ridge  along 
mesal  side  of  dorsal  surface  (Plate  10,  fig.  1).  In  the  penult  legs  of 
male  the  prefemur  is  elevated  into  a  low,  inconspicuous  lobe  at  distal 
end,  while  the  femur  or  fourth  joint  bears  at  its  distal  end  a  conspicu- 
ous lobe  which  is  rather  narrow  from  side  to  side;  this  lobe  projects 
conspicuously  dorsocaudad  over  plane  of  the  articulation  with  tibia, 
both  its  distal  and  its  proximal  surfaces  slanting  in  this  direction  but 
the  proximal  surface  at  an  angle  with  the  distal  so  that  the  lobe 
decreases  distad  in  thickness  as  well  as  in  width. 

Gonopods  of  male  small,  low  conical,  distally  rounded,  pale,  extended 
caudoectad. 

Claw  of  female  gonopods  tripartite;  median  lobe  largest  though 
blunt  and  comparatively  short.  Spines  moderate  in  length  and 
stoutness,  narrowing  a  little  from  base  to  short  apical  portion,  with 
sides  a  little  incurved;  inner  spine  shorter  and  a  little  more  slender 
than  the  outer  (Plate  10,  fig.  2). 

Length  13-15  mm.  A  male  14.25  mm.  long  has  anal  leg  5  mm. 
long  and  tenth  plate  2.6  mm.  wide. 


346  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

TYPE  LOCALITY. —  New  Mexico:  Las  Vegas. 

Found  also  in  New  Mexico  at  Las  Valles  (T.  D.  \.  Cockerell), 
Santa  Fe  (H.  S.  Barber). 

This  is  the  only  member  of  the  genus  thus  far  noted  to  have  the 
penult,  as  well  as  the  anal  legs  of  the  male  pronouncedly  modified. 


POKABIUS    GILAE,    Sp.    nOV. 

Plate  11,  fig.  1. 

DESCRIPTION. —  Dorsum  light  brown  or  testaceous,  with  anterior 
plates  of  more  greyish  cast;  posterior  borders  of  major  plates  in  middle 
and  anterior  region  with  a  blackish  caudal  border.  Head  somewhat 
ferruginous,  darker  caiidad  of  suture  and  especially  in  a  median  black- 
ish spot  contiguous  with  it.  Antennae  brown  proximally,  yellow  at 
tips.  Prosternum  and  prehensors  light  testaceous.  Venter  dilute 
greyish  brown.  Legs  dilute  brown,  the  caudal  pairs  darker  brown, 
the  tarsi  and  mesal  surface  of  anal  pair  lighter. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  60  :  51  :  58  :  70  :  76  :  75.5. 

Head  subcordate,  but  with  caudal  margin  nearly  straight.  Equal 
in  length  and  width.  Marginal  breaks  weak. 

Antennae  as  usual. 

Ocelli  fourteen  to  sixteen  in  four  series  in  type:  1  +  2,  5,  4,  2; 
1  +  5,  5,  3,  2. 

Prosternal  teeth  small.  Median  sinus  small,  shallow,  widely  v- 
shaped.  Spine  slender,  straight  and  long.  Prosternum  1.45  times 
wider  than  long.  Distance  between  chitinous  spots  2.8+  times  the 
width  at  level  of  sinus;  4.6  times  the  dental  line. 

First  dorsal  plate  very  moderately  narrowed  caudad;  1.64  times 
wider  than  long.  Posterior  angles  of  eleventh  and  thirteenth,  and  of 
ninth  on  one  side  rather  weakly  produced  (probably  both  normally 
produced  in  ninth). 

Coxal  pores  small:  2,2,2,2;  2,3,3,2. 

Spines  of  first  legs,  JHHHH  or  M&H;    of   the  second,  |HH;-f|  or 
»    of  the  tnird  anc*  fourth,  o'o'l  M;    of  the  fifth  to  eleventh, 
of  the  twelfth,  iorB;    of  the  thirteenth,  ^-^5    of  the 
penult,  J;  J-JJi,  claws  three;  of  the  anal,  J  J-^H,  claw  one.     Last  three 
pairs  of  coxae  laterally  armed. 

Penult  legs  of  male  without  special  lobes  or  other  modifications. 
Anal  legs  of  male  with  the  third  and  fourth  joints  dorsally  ridged  and 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  347 

produced  into  lobes  at  their  contiguous  ends  in  the  general  way  usual 
in  the  genus,  the  third  bearing  a  longitudinal  dorsal  ridge  elevated 
distally  into  a  lobe  which  at  base  is  contiguous  with  a  lobe  at  proximal 
end  of  a  longitudinal  ridge  on  fourth  joint  (Plate  11,  fig.  1). 

Length  between  9  and  10  mm.  in  type. 

TYPE.— M.  C.  Z.,  No.  184.     Arizona:    Thatcher. 

Known  only  from  the  male.  Collected  under  willow  leaves  at 
edge  of  Gila  River,  April,  1913. 


POKABIUS    BILABIATUS    (Wood). 

Plate  8,  fig.  2. 

Lithobius  bilabiatus  Wood,  Proc.  Acad.  nat.  sci.  Phil.,  1867,  p.  130.  Stuxberg, 
Ofvers.  Vet.-akad.  Forhandl.,  1875,  32,  no.  3,  p.  18,  31,  32.  Chamber- 
lin,  Can.  ent.,  1911,  43,  p.  103. 

Archilithobius  bilabiatus  Stuxberg,  Proc.  Cal.  acad.  sci.,  1876,  7,  p.  138,  139. 

Lithobius  tuber  Bollman,  Proc.  U.  S.  X.  M.,  1887,  10,  p.  256. 

Lithobius  malterris  Kenyon,  Can.  ent.,  1893,  25,  p.  161. 

Poabius  bilabiatus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  6,  p.  153.  Kan. 
univ.  Sci.  bull.,  1913,  7,  p.  167. 

DESCRIPTION. —  Dorsum  from  light  brown  or  testaceous  to  dark 
brown  in  specimens  in  full  color,  with  the  posterior  plates  usually 
somewhat  darker  than  the  others,  while  the  plates  generally  may  be 
paler  along  caudal  border  and  in  a  median  longitudinal  line;  first 
dorsal  plate  either  the  same  as  adjacent  ones  or  it  may  be,  in  fully 
colored  specimens,  decidedly  darker  and  not  much  paler  than  the 
head.  Head  from  brown  of  a  dilute  chestnut  tinge  to  deep  brownish 
black.  Antennae  like  the  head  or  nearly  so,  tip  rufous.  Prosternum 
in  paler  specimens  nearly  like  the  head,  in  darker  ones  paler  than 
head,  dark  brown  but  not  blackish;  prehensors  may  be  a  little  paler 
than  prosternum.  Venter  testaceous  to  brown  of  lighter  shade  than 
dorsum,  caudal  plates  darker  as  usual.  Legs  testaceous  to  clear 
brown  when  in  full  color;  posterior  pairs  much  darker,  usually  much 
like  head  in  color,  their  tarsi  rufous. 

Body  typically  long  and  slender  being  from  8.75  to  9.5  times  longer 
than  width  of  tenth  plate  from  which  it  is  only  moderately  narrowed 
cephalad.  Widths  of  head  and  of  first,  third,  eighth,  tenth,  and 
twelfth  plates  to  each  other  as  47  :  44  :  46  :  52  :  53  :  51. 

Head  considerably  wider  than  long  (e.g.,  47  :  43).  Caudal  margin 
widely  but  only  weakly  incurved,  laterally  widely  curving  to  and 


348  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

about  the  corners.  Sides  between  posterior  corners  and  marginal 
breaks  usually  substraight.  On  caudal  portion  of  head  a  transverse 
semicircular  impression  is  usually  conspicuous,  a  distinctly  impressed 
transverse  sulcus  on  each  side  being  also  evident  in  front  of  caudal 
border.  Finely  and  rather  densely  punctate. 

Antennae  very  short,  reaching  only  to  fourth  and  fifth  body-seg- 
ments. Moderately  attenuated  but  not  very  slender  distally.  Com- 
posed of  the  usual  twenty,  or  occasionally  of  twenty-one  or  twenty- 
three  articles,  which  are  short  but  vary  considerably  in  different  speci- 
mens. 

Ocelli  thirteen  to  seventeen  in  four,  or  less  commonly  in  three,  series  : 
e.g.,  1  +  5,  4,  3;  1  +  4,  5,  3,  1,  a  frequent  arrangement;  1  +  3,  4,  3,  1; 
1  +  3,  4,  4,  1  ;  1  +  3,  4,  3,  2;  1  +  4,  4,  3,  1  ;  1  +  4,  4,  3,  2;  1  +  4,  5,  4, 
2;  1  +  5,  4,  3,  2;  1  +  5,  4,  4,  3.  Single  ocellus  moderate  in  size. 
Series  usually  distinct  and  regular.  Ocelli  of  top  row  not  much  larger, 
the  decrease  ventrad  being  gradual  and  moderate. 

Prosternum  between  1.57  and  1.7,  times  wider  than  long.  Distance 
between  chitinous  spots  in  an  average  specimen  measured  2.4  times 
the  width  at  level  of  bottom  of  median  sinus  and  4  times  the  dental 
line.  Teeth  2  +  2;  line  of  bases  forming  a  weakly  reentrant  angle 
and  line  of  apices  straight  or  nearly  so,  the  inner  tooth  being  usually 
larger;  teeth  acute.  Spine  stout  proximally,  slender  distally  and 
usually  somewhat  curved;  attached  a  little  caudad  of  margin. 

First  dorsal  plate  about  1.7  times  wider  than  long;  surface  finely 
punctate  and  roughened.  Major  plates  mostly  showing  the  short 
transverse  sulcus  toward  each  lateral  margin  near  caudal  third  and 
usually  one  or  two  dot-like  impressions  on  each  side  farther  cephalad. 
Under  lens  showing  a  fine  roughening  which  is  somewhat  more  pro- 
nounced on  caudal  ones.  Posterior  corners  of  all  plates  distinctly 
and  more  or  less  uniformly  simply  rounded. 

Ventral  plates  with  three  longitudinal  sulci  deeply  and  distinctly 
impressed,  a  submedian  transverse  sulcus  also  evident  on  most  plates. 
The  median  longitudinal  sulcus  less  distinct  on  the  anterior  plates. 
On  last  two  plates  a  v-shaped  impression  with  apex  caudad,  this  most 
distinct  on  the  ultimate  one,  the  two  lateral  longitudinal  sulci  being 
evident  in  addition,  at  least  on  the  penult  plate. 

Coxal  pores  moderate,  the  most  proximal  one  on  each  coxa  often 
very  small,  all  circular  or  subcircular:  3,  5,  4,  3;  3,  5,  5,  3;  3,  5,  5,  4; 
3,  6,  4,  4;  4,  4,  5,  4;  4,  5,  5,  3;  4,  5,  5,  4;  4,  5,  6,  5;  4,  6,  6,  4;  4,  6,  6,  5; 
5,  5,  5,  3;  5,  5,  5,  4;  5,  6,  6,  5. 


Spines  of  first  legs,  J-JJJ-i  to  J-J  Jf|;  of  the  second,  ftf$jf  or 
of  the  third  and  fourth,  JHHHH  or  JJ-JJl;  of  fifth  to  tenth, 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  349 


ttH&   of  the  eleventh,  y&K  or  ^^1;   of  the  twelfth, 


of  the  thirteenth  and  penult,  g^ri  2,  those  of  penult  less  often  J;  J  J  3;  2, 
claws  three;    of  the  anal,  in  the  male,  Jii!  V2'o»  oiiis'^'o  or  rarely  only 
-         but  in  the  female  nearly  always,  o^-Jii  rarely  J  J  |  Jl  claw 


071  -   2  o    u     n      e    emae  neary  aways,  o-i    rarey 
one.     Last  three  or  two  pairs  of  coxae  laterally  armed. 

In  female  the  posterior  legs  are  short  and  slender,  wholly  without 
special  lobes  or  furrows.  In  the  male  the  third  article  of  anal  legs  is 
produced  at  distal  end  mesad  or  dorsomesad  into  a  large  lobe  the 
caudomesal  side  of  which  is  convexly  rounded  and  bears  above  five 
or  six,  or  rarely  in  small  specimens  (pseudomaturus)  but  four,  stout 
spines  of  which  the  most  mesal  is  largest,  and  immediately  ectad  of 
these  spines  a  subconic  or  rounded  process  which  projects  dorsad  or 
dorsocaudad  and  bears  distally  a  number  of  very  short  acute  bristles; 
ectad  of  hinge  on  dorsal  side  a  single  spine  in  usual  position.  Fourth 
joint  at  a  little  distance  caudad  of  its  anterior  end  produced  meso- 
dorsad  into  a  very  large  and  conspicuous  flattened  lobe  which  has  its 
anterior  side  nearly  straight  and  transverse  to  axis  of  joint;  caudad 
the  lobe  lowers  obliquely  to  a  low  ridge  which  at  distal  end  of  joint  is 
extended  into  a  small,  conical,  distally  strongly  rounded,  process 
bearing  several  aculeate  hairs,  this  process  being  larger  than  the  simi- 
lar one  on  third  joint;  lobe  densely  clothed  at  its  rounded  apex  with 
short  aculeate  bristles  (cf.  var.  verdescens  Plate  8,  fig.  3).  Penult 
legs  without  lobes  but  the  third,  fourth,  and  fifth  articles,  the  fourth 
most  distinctly,  dorsally  longitudinally  sulcate. 

Gonopods  of  male  small  and  wart-like;  commonly  distally  sub- 
truncate;  bearing  usually  a  robust  bristle  inserted  in  a  distinct  in- 
dentation and  two  smaller  bristles. 

Claw  of  female  gonopods  short  and  relatively  wide;  but  little 
curved;  tripartite,  with  the  median  lobe  largest,  acute;  lateral  divi- 
sions small,  or  very  small,  and  tooth-like,  occasionally  the  inner  one 
absent  and  rarely  the  claw  appearing  subentire  while  in  other  cases  it 
may  show  two  short,  blunt  and  nearly  equal  divisions.  Basal  spines 
of  moderate  size,  with  the  outer  considerably  larger  than  the  inner; 
narrowed  uniformly  from  base  distad  to  beginning  of  about  distal  fifth 
of  length,  where  it  is  very  obliquely  truncate  on  exterior  side,  apex 
acute  (Plate  8,  fig.  2). 

Length  11  to  17.5  mm.  A  male  17  mm.  long  has  anal  leg  4.7  mm. 
long;  antenna  5  mm.  long;  and  tenth  plate  1.93  mm.  wide.  A  female 
15  mm.  long  has  tenth  plate  1.57  mm.  wide. 

Pseudomaturus.  —  Coloration  as  in  maturus  or  somewhat  paler 
in  average  specimens. 

Antennae  as  in  maturus. 


350  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Ocelli  somewhat  fewer  and  frequently  in  but  three  series:  e.g., 
1  +  4,  4,  3. 

Claw  of  female  gonopods  smaller  and  often  with  only  one,  the 
ventral,  of  the  lateral  teeth  distinct.  Bristles  of  joints  somewhat  fewer. 
Spines  as  in  maturus,  or  the  inner  relatively  a  little  smaller. 

Spining  of  legs  as  in  adult,  but  dorsal  spines  of  anal  legs  in  male 
more  often  only  1,  0,  4,  1,0. 

Relatively   somewhat  wider   in   proportion  to   length   than   fully 
matured  specimens. 
Length  9.5-12  mm. 

Praematurus  (late). —  Dorsum  light  brown  or  testaceous,  the  pos- 
terior plates  darker  and  sometimes  verging  toward  chestnut.  Head 
chestnut.  Antennae  at  base  brown  or  light  chestnut  but  paler  over 
most  of  length  with  tip  lightest.  Venter  dilute  brown,  with  the 
anterior  plates  somewhat  darkened  and  the  posterior  ones  more 
strongly  so.  Legs  pale  yellowish  to  pale  greyish  brown,  the  pos- 
terior pairs  in  some  degree  darker  but  pale  distally.  Prosternum 
similar  to  head  but  more  dilute,  the  prehensors  somewhat  lighter. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  29  :  25  :  27  :  31  :  32  :  30.  Proportionately  broader 
than  in  adult,  sometimes  being  only  eight  times  longer  than  width 
of  this  plate. 

Antennae  essentially  as  in  adult. 

Ocelli  small,  well  separated;  in  number  and  arrangement:  e.g., 
1  +  3,  3,  3;  1  +  5,  4,  2. 

Prosternum  nearly  as  in  adult,  but  in  the  one  case  measured  only 
1.5  times  wider  than  long  with  distance  between  chitinous  spots  2.73 
times  width  at  sinus  and  4.1  times  dental  line. 

Coxal  pores  small:  3,3,3,3;  3,4,4,3;  3,3,4,3. 
Claw  of  female  gonopods  small,  thin,  and  pale,  acute,  the  exterior 
or  ventral  tooth  small  and  the  inner  or  dorsal  one  not  at  all  or  but 
weakly  indicated.  Basal  spines  2  +  2,  the  same  form  as  in  adult  or 
nearly  so,  but  the  inner  relatively  much  shorter  and  more  slender, 
acute. 

Spines  of  first  legs,  ori^'i;  °f  tne  second  to  sixth,  lo/^s!^  of  the 
seventh  to  eleventh,  Jo  2  3  2!  of  the  twelfth,  j^'lior  I'l'l'l'l;  of 
the  thirteenth,  j£Ui<»  $&H  to  tJtti  °r  Hrtii;  of  the  penult, 
StrH  of  the  anal  C^XStrH  Last  two  Pairs  of  coxae  ^terally 
armed.  (De  Witt,  la.). 

Immaturus. —  Dorsum  pale  brown,  with  caudal  plates  darker. 
Head  brown  or  dilute  ferruginous  brown,  paler  in  front  of  the  suture. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  351 

Antennae  pale  greyish  brown  or  yellowish,  brighter  distad.  Pro- 
sternum  yellowish  brown,  prehensors  lighter.  Venter  pale,  caudal 
plates  more  densely  pigmented,  yellowish  to  orange.  Legs  pale, 
brighter  at  tips,  the  posterior  pairs  more  pigmented,  brightest  at  tips 
like  the  others. 

Body  only  7.5  times  longer  than  width  of  tenth  plate  thus  still 
wider  proportionately  than  in  praematurus.  Widths  of  head  and 
usual  series  of  plates  to  each  other  as  22  : 18  : 19  : 22.5  : 23  : 22. 

Head  relatively  longer  than  in  adult  in  specimens  examined  (cf  cf) 
being  but  little  wider  than  long. 

Antennae  very  short  with  20  articles  already  present,  these  short  and 
very  short;  antennae  submoniliform. 

Ocelli  mostly  small  and  well  separated;  single  ocellus  relatively 
large;  ocelli  of  top  row  largest  of  seriate  ocelli.  Ocelli  in  three  series: 
e.g.,  1  +  4,2,2;  1  +  3,  4,  2. 

Prosternum  1.54  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.85  times  width  at  sinus;  4.44  times  dental  line.  Teeth 
2  +  2,  rather  small,  line  of  apices  a  little  recurved.  Spine  and  sinus 
as  in  praematurus. 

Coxal  pores:  2,  2,  3,  2;  2,  3,  3,  2;  2,  3,  4,  3. 

Spines  of  first  legs,  iHHrS'i  to  g^ft  and  Hm;  of  the  second, 
H*il  mil  to  mS'and  SHJS1-;  of  the  third  and  fourth,  ffiffi 
to  J4tH;  of  the  fifth  to  seventh,  ^  J'  £  \  to  \  |j;  J- £|;  of  the  eighth  and 
ninth, '£{H$S  to  m*  2;  of  the  tenth,  ffiffi  to  °J;l,ij;  of  the 
eleventh,  o'o ill;  of  the  twelfth,  orJ-J  Jl;  of  the  thirteenth,  Hili  or 
ttUi;  of  the  penult,  J-^TOJ  of  the' anal  (<?c7 ),  %ffi$  i'ftftj 
(observed  on  one  side).  Last  pair  of  coxae  laterally  armed. 

Anal  legs  of  male  with  third  joint  but  little  produced  mesad  at  distal 
end.  Fourth  joint  already  showing  in  a  distinctly  developed  form  the 
flattened  mesodorsal  process  toward  its  proximal  end,  but  this  process 
relatively  much  shorter  than  in  the  maturus  and  the  angle  formed  by 
anterior  and  posterior  edges  much  more  obtuse,  the  anterior  side 
oblique,  not  nearly  at  right  angles  as  in  adult,  and  the  lobe  not  showing 
the  acuteate  hairs;  the  smaller  subconical  processes  at  distal  ends  of 
third  and  fourth  joints  of  adults  not  yet  at  all  indicated. 

Length  6.5—7.5  mm.  A  male  7.5  mm.  long  has  antennae  3  mm.  and 
anal  leg  2.6  mm.  long  with  width  of  tenth  plate  1  mm.  (DeWitt  and 
Tama,  Iowa). 

Pullus  IV  (Larva  IV).—  Dorsum  pale  yellowish  white  with  the  head 
more  pigmented,  yellowish.  Antennae  and  legs  whitish.  Prosternum 
and  prehensors  like  head.  Venter  nearly  same  as  dorsum  of  body. 


352  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Body  more  strongly  narrowed  caudad  of  tenth  plate  than  in  adult. 
Ratio  of  widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth 
plates  to  each  other  as  32  :  26.5  :  28  :  30  :  28  :  23. 

Head  equal  in  length  and  breadth.  Caudal  margin  straight  or  a 
little  excurved. 

Antennae  composed  of  seventeen  articles  which,  excepting  the  first 
three  and  the  ultimate  one,  are  very  short;  submoniliform;  sub- 
sparsely  hirsute. 

Ocelli  1  +  2, 1.  The  first,  or  caudal,  ocellus  of  upper  series  relatively 
very  large,  as  large  as  or  larger  than,  the  single  one  and  much  larger 
than  others  of  series. 

Prosternum  1.54  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.55  times  width  at  sinus  and  3.53  times  dental  line.  Teeth 
2  +  2,  small,  subequal  with  line  of  apices  straight  or  slightly  recurved. 
Spine  and  sinus  as  in  older  stages,  or  former,  proportionately  to  teeth, 
somewhat  stouter. 

A  single  coxal  pore  present  on  each  twelfth  coxa. 

Spines  of  first  legs,  {nnnri;  of  the  second  to  eighth,  <nnnri;  of  the 
ninth,  <HHJ'°' J  or  jfjti;  of  the  tenth  to  twelfth,  g$$U  '  (De  Witt, 
la.). 

Last  three  pairs  of  legs  showing  only  as  short  pale  buds  in  which  the 
joints,  excepting  the  coxa,  are  not  as  yet  distinctly  indicated. 

TYPE  LOCALITY. —  Illinois:   Rock  Island. 

Found  also  in  Illinois  at  Franklin  Grove,  Peoria,  Sterling.  Iowa: 
De  Witt,  Tama.  Nebraska:  Grand  Island.  Kansas:  Cowley, 
Douglas,  Graham,  Sumner,  and  Trego  counties  (fide  Gunthorp). 
Indiana:  Bloomington  (Bollman).  Minnesota:  Winona  (Holzinger 
coll.,  seq.  Bollman).  Wisconsin:  Devil's  Lake.  Mississippi:  Byram. 

This  is  apparently  a  very  common  species  in  the  states  of  the 
northern  Mississippi  valley,  ranging  also  southward  toward  the  Gulf 
as  indicated  by  its  occurrence  in  Mississippi.  It  varies  much  in  many 
of  its  features  and,  from  material  available  for  study,  seems  to  have  a 
considerable  tendency  toward  the  formation  of  minor  forms  or  varie- 
ties; but  intergradation  is  frequent  and,  in  spite  of  differences  in  local 
modes,  it  seems  inadvisable  to  attempt  their  separation  as  varieties, 
except  in  the  case  of  verdescens,  until  the  species  is  more  thoroughly 
known  and  the  significance  of  the  differences  indicated  more  clearly 
understood.  The  species  offers  excellent  material  for  a  careful  study 
in  variation. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  353 


POKABIUS  BILABIATUS  VERDESCENS  Chamberlin. 
Plate  8,  fig.  3. 

Poabius  verdescens  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  6,  p.  154,  pi.  13, 
fig.    1. 

DESCRIPTION. —  Dorsum  sometimes  from  clear  brown  to  light 
chestnut  with  first  plate  and  caudal  borders  of  others  dark  but  more 
often  brown  of  a  pronounced  olivaceous  cast.  Head  either  like 
dorsum  but  usually  ferruginous  brown  or  chestnut,  dusky  caudad  of 
the  suture.  Prosternum  olivaceous  to  dark  brown.  Venter  typically 
light  to  dark  olivaceous  though  sometimes  clear  broWn.  Legs  pale 
olivaceous  to  brown  with  posterior  pairs  darker  as  usual. 

Body  more  robust  than  in  bilabiatus  proper,  varying  from  only  6.7 
to  8  times  longer  than  width  of  tenth  plate.  Widths  of  head  and  of 
first,  third,  eighth,  tenth  and  twelfth  plates  (in  d")  to  each  other  as 
64  :  63  :  63+  :  71  :  71  :  64. 

Antennae  typically  somewhat  longer  than  in  bilabiatus,  reaching 
seventh  segment. 

Ocelli  as  in  the  species. 

Prosternum  typically  relatively  narrower  than  in  the  species,  being 
from  1.5  to  1.57  times  wider  than  long.  Distance  between  chitinous 
spots  2.5  to  2.8  times  width  at  sinus  and  4  to  4.5  times  dental  line. 
Line  of  apices  of  teeth  straight  or  very  nearly  so. 

Spining  of  legs  very  nearly  as  in  bilabiatus,  excepting  that  the  ventral 
spines  of  the  thirteenth  legs,  in  all  specimens  studied,  is  0,  0,  3,  3,  2, 
a  formula  sometimes  present  but  not  usual  in  the  species. 

Anal  legs  of  male  as  described  for  bilabiatus  proper. 

Female  gonopods  essentially  as  in  the  species. 

Length  11-18  mm. 

TYPE  LOCALITY. —  Illinois :   Peoria ! 

Taken  also  in  Iowa:  Tama!  Mongona!  Boone!  Mississippi:  Canton! 

This  varietal  form  occurs  in  the  same  general  region  as  the  species 
proper.  Judging  from  limited  number  of  specimens  of  the  immature 
stages  examined,  the  ratio  of  length  to  width  of  tenth  plate  increases 
with  development  in  bilabiatus,  the  slenderness  becoming  more  and 
more  pronounced;  whereas,  on  the  other  hand,  in  verdescens  it  de- 
creases. Study  of  more  extensive  collections  may  break  down  the 
seeming  differences  between  the  two  forms;  but  if  so  the  range  of 
variation  in  the  species  will  be  found  to  be  unusually  great. 


354  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

POKABIUS  DISANTUS,  Sp.  HOV. 

Plate  9,  fig.  3. 
Lithobius  davigerens  Chamberlin,  Pomona  coll.  journ.  ent.,  1910,  2,  p.  373. 

DESCRIPTION  —  Dorsum  testaceous.  Head  dusky  behind  suture 
and  abruptly  lighter  in  front  of  it.  Antennae  light  distad.  Pro- 
sternum  dusky  testaceous  or  yellowish;  prehensors  yellow.  Venter 
dilute  yellow,  caudal  plates  dusky  yellow.  Legs  very  pale,  the  caudal 
pairs  more  densely  pigmented,  bright  yellow. 

Body  9  to  10  times  longer  than  width  of  the  tenth  plate.  Widths 
of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to  each 
other  as  48  :  48  : 49  :  54  :  54  : 52.5  (cf ). 

Head  (in  cf)  slightly  longer  than  wide  (49  :48).  Weakly  sub- 
sparsely  punctate.  Bristles  moderately  long,  sparse. 

Antennae  short;   articles  twenty,  short,  subcylindric,  uniform. 

Ocelli  ten  to  twelve  in  three  series:  e.g.,  1  +  3,  4,  3;  1  +  4,  3,  2; 
1  +  4',  4,  3. 

PrOsternum  1.48  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.7  times  width  at  level  of  bottom  of  median  sinus;  4.56 
times  the  dental  line.  .Teeth  small,  acute,  with  line  of  apices  recurved. 
Spine  moderately  stout  at  base,  bristle-like  distally,  straight. 

First  dorsal  plate  1.7  times  wider  than  long;  sides  gently  convex, 
considerably  converging  caudad  to  and  about  the  rounded  caudal 
corners;  widest  just  cephalad  of  middle.  Caudal  corners  of  ninth, 
eleventh,  and  thirteenth  dorsal  plates  obliquely  excised. 

Coxal  pores  small,  circular:  2,  2,  2,  2;  2,  3,  3,  2. 

Spines  of  first  legs,  <HnrH  to  OTO' i5  of  the  second,  onrHn  or 
flrttH  of  the  third  to  fifth,  torts!  i';  of  the  sixth,  [HHHH  or  JftH; 
of  the  seventh  and  eighth,  J-J-tJl;  of  the  ninth,  jHHril;  of  the  tentn> 
57oy| 372!  of  the  eleventh,  offtl  or  Joilil;  of  the  twelfth,  JJJJzJ 
of  the  thirteenth,  J-JJ-J-J;  of  the  penult,  07173;  37i>  claws  three;  of  the 
anal,  o! i'.l',2,o  °r>  less  commonly,  (cf ),  oriHrH-  None  of  the  coxae 
armed  laterally. 

Anal  legs  of  male  with  the  third  joint  elevated  on  dorsomesal  side 
into  a  conspicuous,  strongly  chitinized  ridge  which  is  highest  a  little 
caudad  of  middle  of  its  length,  its  edge  rounding  down  evenly  both 
ways;  bearing  two  stout  dorsal  spines  on  caudal  slope  of  ridge  one 
behind  the  other,  not  in  a  transverse  line  at  end  of  joint  as  in  daviger- 
ens. Fourth  article  crassate,  longitudinally  furrowed  along  dorso- 


CHAMBERLIN :   NORTH    AMERICAN    LITHOBIIDAE.  355 

mesal  surface,  the  furrow  limited  on  mesal  side  by  a  low  ridge  which 
is  elevated  at  proximal  end  into  a  more  transverse  conspicuous  lobe, 
thin  in  a  nearly  cephalocaudad  direction  but  wider  transversely,  con- 
cave on  caudal  side  and  projecting  cephalomesad ;  third,  fourth,  and 
fifth  joints  longitudinally  furrowed  on  ectal  side  toward  dorsal  surface 
(Plate  9,  fig.  3). 

Claw  of  female  gonopods  slightly  curved;  distinctly  tripartite, 
with  the  median  lobe  much  longest;  the  dorsal  and  ventral  at  about 
same  level  but  the  ventral  smaller  and  more  acute.  Basal  spines 
moderately  long  and  slender;  sides  incurved  between  base  and 
acuminate  distal  portion;  a  denticule  at  base  of  acuminate  portion 
on  each  side  with  sometimes  a  second  one  farther  toward  apex. 

Length  9-11  mm.  A  male  9  mm.  long  has  antenna  3.25  mm.  and 
anal  leg  3—  mm.  long,  with  tenth  plate  1  mm.  wide. 

TYPE  LOCALITY. —  M.  C.  Z.  No.  276. —  California:  Laurel  Canyon, 
Los  Angeles  Co.,  June,  1909. 

Found  also  in  California  at  Eaton's  Canyon,  April,  1913. 

This  species  much  resembles  P.  damgerens  but  is  clearly  distinct 
from  that  species  in  spining  of  legs  as  well  as  in  the  form  of  lobes 
of  anal  legs  and  in  other  features. 

POKABIUS  UTAHENSIS  (Chamberlin). 
Plate  10,  fig.  3,  4. 

Lithobius  utahensis  Chamberlin,  Proc.  U.  S.  N.  M.,  1901,  24,  p.  22  (nee  Ann. 

Ent.  soc.  Amer.,  1909,  2,  p.  187). 

Lithobius  obesus  Bollman  (nee  Stuxberg),  Proc.  U.  S.  N.  M.,  1888,  11,  p.  347. 
Poabius  utahensis  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  5,  p.  153. 

DESCRIPTION. —  Dorsum  yellow,  frequently  of  a  dilute  orange  tinge. 
Head  pale  orange,  commonly  with  the  frontal  region  somewhat  paler. 
Antennae  like  the  head  proximally,  yellow  distally.  Prosternum  and 
prehensors  like  the  head.  Venter  pale  yellow,  darker,  dilute  orange, 
caudally.  Legs  pale,  the  posterior  pairs  more  densely  pigmented  as 
usual,  bright  yellow  or  dilute  orange. 

Body  in  females  on  average  shorter  and  relatively  broader  than  in 
males,  being  mostly  from  8  to  8.5  times  longer  than  width  of  tenth 
plate  in  the  former,  and  in  male  often  near  9.5  times  longer.  Widths 
of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  in  an 
average  individual  to  each  other  as  23  :  20  :  21  :  24  :  24.5  :  23. 

Head  commonly  slightly  longer  than  wide  (45  :  44).     Caudal  margin 


356  BULLETIN:  MUSEUM  or  COMPARATIVE  ZOOLOGY. 

straight  or  very  weakly  excurved.  Head  in  front  of  eyes  rather 
broadly  rounded,  subsemicircular.  Smooth.  Hairs  moderately  long, 
sparse. 

Antennae  very  short,  reaching  fourth  or  beginning  of  fifth  segment. 
Articles  twenty  or  sometimes  twenty-one  or  twenty-two;  mostly 
very  short,  decreasing  in  size  from  the  second  to  the  ultimate. 

Ocelli  five  to  eleven,  but  mostly  five  to  eight,  in  two  longitudinal 
series:  e.g.,l  +  1,3;  1  +  3,3;  1+2,2;  1  +  2,3;  1  +  5,2;  1+5,3. 
Ocelli  often  irregular  in  form,  size  and  arrangement  and  varying 
considerably  in  size  in  different  individuals.  Single  ocellus  of  about 
same  size  as  the  larger  ones  in  series. 

Prosternum  1.5  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.33  times  width  at  level  of  bottom  of  sinus;  3.5  times  the 
dental  line.  Median  sinus  moderately  wide,  v-shaped.  Teeth  small 
and  pale  or  scarcely  darkened.  Spine  moderately  stout  at  base, 
bristle-like  distally,  nearly  straight. 

First  dorsal  plate  about  1.66+  times  wider  than  long;  sides  cepha- 
lad  of  the  rounded  corners  nearly  straight  and  also  nearly  parallel. 
Posterior  angles  of  none  of  the  plates  produced.  Plates  smooth  and 
shining. 

Coxal  pores  small,  with  the  most  proximal  one  on  each  coxa  often 
minute:  2,2,2,2;  2,3,3,2;  2,3,3,3;  3,3,3,3. 

Spines  of  first  legs,  loixli  or  sometimes  oioivli;  of  the  second  to 
seventh,  J^H;  of  the  eighth  to  eleventh,  orll i;  of  the  twelfth, 
TO7B  or 'sometimes  J-J-Jtk  of  the  thirteenth',  gfJii  or,  less  com- 
monly, l^.l:\;  of  the  penult,  J-J-JJi  or  JJ J J},  claws  three;  of  the 
anal,  Hrl^  o  or  orHrH>  c^aw  one-  Last  pair  of  coxae  laterally  armed. 

Anal  legs  of  male  with  the  third  article  typically  produced  at  distal 
end  mesad  or  dorsomesad  into  a  conspicuous  lobe  which  is  thin  in 
cephalocaudal  direction  and  is  contiguous  with  a  corresponding  lobe 
at  proximal  end  of  fourth  joint  which  bears  below  apex  a  patch  of 
short  spinules  projecting  caudad;  third  joint  typically  with  a  wide 
longitudinal  furrow  on  mesal  or  mesodorsal  surface,  this  limited 
dorsally  or  ectally  by  a  longitudinal,  ridge-like,  elevation;  the  two 
mesal  spines  of  dorsal  surface  of  third  joint  short,  distally  rounded,  and 
finely  serrulate,  projecting  cephalad  from  lobe;  fourth  joint  longi- 
tudinally furrowed  along  dorsomesal  surface,  the  furrow  ending 
anteriorly  at  base  of  lobe  previously  mentioned,  deepest  cephalad; 
fourth  joint  more  or  less  constricted  or  excavated  just  caudad  of  the 
lobe  and  then  thickening  caudad,  swollen  (Plate  10,  fig.  3).  The 
lobe  formed  by  the  extension  of  third  and  fourth  joints  at  their  con- 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  357 

tiguous  ends  subject  to  considerable  variation  in  size.  Penult  legs  of 
male  slightly  swollen  but  not  otherwise  specially  modified.  In  the 
female  the  posterior  legs  are  moderately  slender. 

Gonopods  of  male  pale;  moderately  narrowed  distad  with  apex 
rounded;  bearing  one  moderately  long  bristle. 

Claw  of  female  gonopods  short  and  relatively  wide,  rather  strongly 
curved;  claw  tripartite,  all  lobes  distinct,  the  middle  one  a  little 
larger  than  the  others.  Spines  2  +  2;  rather  robust,  and  typically 
more  or  less  clavately  widening  from  base  to  the  acuminate  apical 
portion,  the  outer  side  of  which  is  the  longer  and  is  finely  crenulate 
or  serrulate  (Plate  10,  fig.  4).  Inner  side  of  first  article  straight  or 
nearly  so. 

Length  of  females  7.5-9.5  mm.;  of  males  8.5-10.5  mm.  A  male 
8.5  mm.  long  has  antennae  2.4  mm.  and  anal  leg  2.6  mm.  long;  width 
of  tenth  plate  .896  mm. 

Pscudomaturus. —  Yellow,  with  less  of  orange  tinge  than  in  maturus. 

Ocelli  averaging  in  number  toward  lesser  limit  given  for  maturus. 

Claw  of  female  gonopods  paler  and  smaller  with  lobes  more  slender 
and  acute.  Spines  a  little  less  robust  with  inner  relatively  a  little 
shorter. 

Length  6.5-7.5  mm. 

Praematurus. —  Coloration  nearly  as  in  older  stages  but  lighter 
yellow  with  less  of  orange  tinge. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  as 
33.5  :  30  :  31  :  36  :  38  :  37. 

Antennae  very  short;  full  number  of  articles  present. 

Ocelli  1  +  1,  2;    1  +  3,  2.     Single  ocellus  variable  in  relative  size. 

Prosternum  nearly  as  in  older  stages.  1.6  times  wider  than  long. 
Distance  between  chitinous  spots  2.36  times  width  at  sinus;  3.7 
times  dental  line. 

Coxal  pores:  2,  2,  2,  2;  2,  2,  3,  2;  2,  3,  3,  2. 

Female  gonopods  with  joints  short,  especially  the  second  and  third. 
Claw  small,  thin  and  pale;  the  three  teeth  evident,  though  slender  and 
acute.  Third  joint  mostly  with  one  short  bristle;  second  with  two 
or  three;  first  with  four  or  five.  Spines  2  +  2;  the  inner  much 
shorter  and  more  slender  than  the  outer  which  is  much  as  in  maturus 
but  smaller  and  often  not  at  all  clavately  widened  distad. 

Gonopods  of  male  small  and  wart-like;  as  yet  glabrous. 

Spines  of  first  legs,  o'o  S'H  or  o'o  o  H;    of  the  second,  o'o  I'll  or 

W^-1-  of  the  third,  ttffi'or  H£j£|;  of  the  fourth,  J-ft  H&  of  the 
of  the  seventh  and  eighth,  £  J  o.  H  or 


358  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

of  the  ninth  to  eleventh,  $-%%$%',  of  the  twelfth,  l^l'l'l;  of  the  thir- 
teenth, J;°o;I;H  or  o'roiHi;'  of  the  penult,  kml>  daws  three;   of  the 


anal,  o!  i]  3,'  •>,'  o-     Last  pair  of  coxae  laterally  armed. 

Anal  leg  of  male  modified  as  in  maturus  but  lobe  at  junction  of  third 
and  fourth  joints  somewhat  less  developed  with  the  spinules  on  its 
caudal  surface  fewer. 

Length  5.5-6.5  mm.  A  female  6.5  mm.  long  has  tenth  plate  .73  mm. 
wide,  thus  being  nine  times  longer  than  width  of  this  plate. 

Immaturus.  —  Dorsum  very  pale,  whitish,  the  caudal  plates  tinged 
with  yellow.  Head  dilute  orange.  Prosternum  and  prehensors  like 
head.  Venter  whitish,  caudal  plates  tinged  with  yellow.  Legs  and 
antennae  whitish. 

Antennae  already  with  twenty  articles  but,  especially  the  median 
and  distal  ones,  considerably  shorter  than  in  the  praematurus. 

Ocelli  1  +  2.  The  single  ocellus  smaller  than  the  other  two,  the 
caudal  one  of  which  is  largest.  Pale. 

Prosternum  with  teeth  small  and  pale.  Spines  at  base  relatively 
to  teeth  somewhat  stouter  than  in  maturus,  abruptly  narrowed  near 
middle  to  bristle-like  form.  In  specimen  measured  only  1.45  times 
wider  than  long.  Distance  between  chitinous  spots  3  times  width  at 
sinus;  4.25  times  dental  line. 

Coxal  pores  very  small:  1,  2,  2,  2;  2,  2,  2,  2. 

Gonopods  of  male  small,  whitish,  glabrous. 

Gonopods  of  female  short  and  pale.  Claw  appearing  as  a  small, 
acute  pale  point  with  no  indication  of  lateral  teeth  or  in  earlier  stages 
claw  wholly  absent.  Third  and  second  articles  glabrous;  the  first 
with  one  or  two  bristles.  Spines  1  +  1  or  1  +  2,  small  and  acute,  pale. 

Spines  of  first  legs,  o'  o  o  o'  1;  of  the  second  to  fourth,  OTTI'  1;  of  the 
fifth,  K-|  I  \  or  (HHrH;  of  sixth  to  tenth,  J-J-J;  J  \;  or  in  part,  especially 
in  the  more  anterior  ones,  J-JJ-JS;  of  the  eleventh,  mHHi  of  the 
twelfth,  o  o'i'H;  °f  the  thirteenth  same  as  twelfth,  or  J'  o  2*2  i;  of  the 
penult,  S&JU  KJti  or  }£H£  of  the  anal,  H*H  or  ^ft' 
None  of  coxae  as  yet  laterally  armed. 

Anal  legs  of  male  with  fourth  joint  constricted,  or  excavated,  near 
proximal  end  and  the  third  and  fourth  joints  more  or  less  produced 
at  junction  into  a  lobe  similar  to,  but  usually  less  marked  than,  that  in 
older  stages,  the  spinules  also  present.  Dorsal  spines  of  third  joint 
less  modified. 

Length  of  principal  specimen  described,  5.4  mm. 

Agenitalis  II.  Whitish,  of  faint  yellowish  tinge  caudad.  Head 
dilute  orange  or  yellowish.  Antennae  and  legs  whitish. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  359 

Antennae  composed  of  seventeen  articles  which,  excepting  the  first 
few  and  the  ultimate  one,  are  very  short.  Bristles  proportionately 
long  and  straight,  not  dense. 

Ocelli  1  +  1  or  1  +  2.     First  ocellus  in  series  largest. 

Prosternum  with  teeth,  sinus  and  spines  as  in  immaturus  or  nearly 
so.  1.425  times  wider  than  long,  thus  narrower  than  in  immaturus, 
the  proportionate  width  increasing  with  development  throughout. 
Distance  between  chitinous  spots  2.66+  times  width  at  level  of  bot- 
tom of  median  sinus;  3.42  times  dental  line. 

Coxal  pores  minute:  1,  1,  1,  1. 

Gonopods  not  yet  exposed. 

Spines  of  first  legs,  °'  %  g-  £  °;  of  the  second  to  twelfth,  g-  JHJ'-J-J;  of  the 
thirteenth,  JJJ};!;  of 'the  penult,  JJiH;  of  the  anal, '  J  J  £-J-jj  or 
o!  i'.  2^  i|  o-  No  lateral  spine  on  any  coxae. 

Anal  legs  already  nearly  as  in  older  stages  but  lobes  weaker. 

Length  3.5-4.5  mm. 

TYPE  LOCALITY. —  Utah:   Neff's  Canyon,  Salt  Lake  Co.! 

Taken  also  in  Utah  in  Mill  Creek  Canyon,  City  Creek  Canyon, 
Farmington  Canyon,  Ogden  Canyon,  Cottonwood  Canyon,  American 
Fork  Canyon,  Provo  Canyon;  Spanish  Fork  Canyon,  and  other 
canyons  of  the  Wahsatch  Mts.,  where  it  is  common  under  damp  leaves 
along  the  streams. 

POKABIUS  SOKOVUS  (Chamberlin). 

Plate  11,  fig.  2,  3. 

Lithobius  sokovus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1909,  2,  p.  189. 
Poabiits  sokovus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  5,  p.  153. 

DESCRIPTION. —  Dorsum  and  venter  very  pale  testaceous  to  whitish 
yellow.  Head  and  antennae  with  prosternum  and  prehensors  pale 
brown.  Legs  from  whitish  to  pale  yellow. 

Body  of  type  8.8  times  longer  than  width  of  tenth  plate.  Widths 
of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to  each 
other  as  23  :  22.5  :  23  :  25  :  25  :  24. 

Head  well  rounded  behind  but  the  caudal  margin  straight.  A  little 
wider  than  long  (23  :  22.5). 

Antennae  short,  reaching  the  fifth  segment  as  usual.  Articles 
nineteen  to  twenty,  short,  with  ultimate  equalling  the  two  preceding 
together. 

Ocelli  six  to  eight  arranged  in  two  series:  e.g.,  1  +  3,  2;  1  +  4,  2; 
1  +  4,  3.  Single  ocellus  small,  not  much  differing  in  size  from  caudal 
ocelli  of  series. 


360  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Prosternum  1.55  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.9  times  width  at  sinus,  the  anterior  portion  of  prosternum 
being  narrow  with  sides  strongly  converging;  4.37  times  the  dental 
line.  Teeth  very  small  and  pale,  the  inner  the  larger  and  the  line  of 
apices  thereby  nearly  straight.  Median  sinus  rather  small,  v-shaped. 

First  dorsal  plate  with  sides  in  front  of  the  well-rounded  caudal 
corners  nearly  parallel.  Posterior  angles  of  none  of  the  plates  pro- 
duced. 

Coxal  pores  small,  circular:    1,  2,  2,  2;  2,  2,  2,  2. 

Spines  of  first  legs,  [HrHri  or  oo'l'lii    of  the  second  and  third, 

IHHfK;  °f  the  fourth  and  fifth>  otcBri  or  roHH;  of  the  sixth' 

{{llii;  of  the  seventh  to  eleventh,  K$Jf;  of  the  twelfth  and  thir- 
teenth, ^  o!  2!  a!  2?  of  the  penult  VlHhH'  claws  two  or  an  anterior  ac- 
cessory minute;  of  the  anal,  OTI^O,  c^aw  one-  Last  pair  of  coxae 
laterally  armed. 

Anal  legs  of  male  short  and  moderately  inflated.  Third  joint  ele- 
vated dorsally  in  a  longitudinal  ridge  and  at  distal  end  in  a  transverse 
one  much  as  in  utahensis;  fourth  joint  dorsally  with  a  conspicuous 
longitudinal  furrow  which  is  widest  and  deepest  proximally,  the  furrow 
being  limited  along  the  sides  by  a  low  ridge-like  elevation  and  at  the 
anterior  end  by  the  usual  more  conspicuously  elevated  lobe  which 
extends  dorsomesad  and  which  is  continuous  on  each  side  with  the 
low  longitudinal  ridges,  the  lobe  concave  on  its  caudal  surface,  the 
concavity  being  a  continuation  of  the  dorsal  furrow  (Plate  11,  fig.  2). 

Claw  of  female  gonopods  tripartite.  Spines  moderately  long  and 
slender,  with  the  sides  subparallel  or  a  little  incurved  between  base 
and  short,  acuminate,  distal  portion  (Plate  11,  fig.  3). 

Length  6.5-9  mm. 

TYPE  LOCALITY. —  Nevada:  Las  Vegas  (1909). 

Dug  up  in  loose  soil  in  a  garden.  The  female  is  not  quite  fully 
mature. 


POKABIUS  CLAVIGERENS  Chamberlin. 
Plate  9,  fig.  1,  2. 

LithoMus  davigerens  Chamberlin,  Proc.  Acad.  nat.  sci.  Phil.,  1903,  66,  p.  159. 

Pomona  coll.  journ.  ent.,  1910,  2,  p.  373  (in  part). 
Lithobius  manni  Chamberlin,  Pomona  coll.  journ.  ent.,  1910,  2,  p.  373  (pseudo- 

maturus  var.). 
Poabius  davigerens  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  5,  p.  153. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  361 

DESCRIPTION. —  Testaceous  or  light  brown,  or  rarely  of  greyish 
cast  suffused  with  violaceous  (freshly  moulted  specimens)  to  darker 
brown  with  caudal  plates  commonly  somewhat  darker,  chestnut  or 
subf erruginous ;  posterior  borders  of  plates  often  darker  and  also  in 
part  with  an  interrupted  longitudinal  median  stripe.  Head  mostly 
of  a  dilute  ferruginous  tinge,  darker  caudad  of  suture.  Antennae 
similar  to  head,  but  typically  pale  proximally  and  at  very  tips.  Pro- 
sternum  usually  much  lighter  than  the  head.  Venter  pale,  the  more 
caudal  plates  more  deeply  pigmented,  yellow  to  somewhat  ferruginous. 
Legs  pale,  the  caudal  pairs  more  deeply  pigmented,  brown,  often 
lighter  distally  and  along  mesal  surface  where  color  may  be  yellow  or 
some  shade  of  orange. 

Body  moderately  robust,  being  typically  from  7.75  to  8.5  times 
longer  than  width  of  tenth  plate,  but  sometimes  only  7  times  longer 
(var.  manni}.  Widths  of  head  and  of  first,  third,  eighth,  tenth,  and 
twelfth  plates  to  each  other  as  44  :  41  :  43  :  53  :  54  :  51,  the  first  plate 
being  clearly  narrower  than  the  third. 

Head  from  considerably  wider  than  long,  as  in  the  type  (44  : 41)  to 
nearly  equal  in  length  and  breadth  or  but  slightly  wider  (only  about 
29.5:29  in  var.  manni).  Cordate,  considerably  narrowed  caudad 
of  breaks  and  strongly  so  in  front  of  eyes.  The  most  distinct  sulcus  is 
the  median  longitudinal  one  in  front  of  the  suture  which  unites  with  a 
transverse  one  parallel  with  and  a  little  in  front  of  the  suture.  A  short 
oblique  sulcus,  not  very  deeply  impressed,  each  side  of  the  middle  just 
back  of  the  suture  the  inner  end  of  which  is  near  a  small,  pit-like 
impression.  The  usual  semicircular  depression  on  caudal  portion 
shallow  and  wide.  Irregularly  punctate. 

Antennae  short,  the  usual  twenty  articles  short,  decreasing  distad; 
reaching  to  fifth  or  sixth  segment. 

Ocelli  twelve  to  twenty-five  but  mostly  sixteen  to  twenty-five  (dan- 
ger en^,  forma  typica),  arranged  in  three  or  four,  or,  more  rarely,  even 
in  five  or  six,  series:  e.g.,  1  +  5,  5,  3;  1  +  5,  5,  4,  2;  1  +  5,  5,  4,  1; 
1  +  5,  5,  3,  2;  1  +  5,  5,  5,  2;  1  +  3,  5,  6,  3;  1  +  6,  5,  5,  1;  1  +6,  6, 
6,  5,  1;  1  +  1,  5,  6,  6,  5,  1.  Ocelli  frequently  well  separated,  not 
contiguous,  regular  in  form  and  arrangement,  decreasing  cephalad, 
black.  Single  ocellus  large. 

Prosternum  1.53  to  1.58  times  wider  than  long.  Distance  between 
chitinous  spots  2.3+  to  2.55  times  width  at  level  of  bottom  of  sinus; 
4.2  to  4.4  times  as  long  as  the  dental  line.  Sinus  wide,  strictly  v- 
shaped  (manni},  or  with  sides  concave  and  widely  rounded  at  bottom 
(forma  typica).  Spines  moderately  stout  at  base  but  attenuated  and 


362  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

bristle-like  distad,  straight.  Teeth  small,  the  mesal  one  of  each  pair 
the  larger  so  that  line  of  apices  is  commonly  almost  straight. 

First  dorsal  plate  moderately  narrowed  caudad;  about  1.85  times 
wider  than  long;  sides,  except  at  ends,  nearly  straight  or  but  gently 
convex,  moderately  converging  caudad.  Dorsal  plates  mostly  show- 
ing two  short,  deeply  impressed,  diverging,  longitudinal  lines  at  ante- 
rior end  close  to  median  line.  Weakly  roughened.  Posterior  corners 
of  ninth,  eleventh,  and  thirteenth  dorsal  plates  mostly  obliquely  and 
somewhat  concavely  excised;  others  with  corners  less  extensively 
excised  or  else  subrectangular. 

Ventral  plates  with  each  lateral  longitudinal  furrow  on  anterior  por- 
tion ending  abruptly  in  a  deeper  pit  or  bending  directly  ectad,  espe- 
cially so  on  the  anterior  plates.  The  median  longitudinal  sulcus 
represented  on  anterior  plates  mostly  by  a  pit-like  depression,  but, 
more  elongate  on  posterior  plates.  Last  two  plates  of  leg-bearing 
segments  with  corresponding  coxae  and  also  succeeding  sternite  sub- 
densely  pilose. 

Coxal  pores  small,  with  the  most  proximal  on  each  coxa  often 
minute,  with  series  sometimes  irregular  and  even  appearing  double  on 
some  coxae :  3,  4,  4,  3,  the  most  usual  numbers  and  arrangement,  to 
4,  4,  4,  4  and  3,  4,  3  +  3,  3. 

'  Spines  of  first  legs,  57070  to  KHiJ  of  the  second  and  third, 
BrHrH  to  jHrir3;i;  of  the  fourth  to  eleventh,  o^UJ;  of  the  twelfth, 
orsrli;  2 or  £$£«  2;  of  the  thirteenth  and  penult,  J-J-J- J-},  claws  3 ;  of  the 
anal,  oriHh;  o  (male),  or  oriHHrrL  sometimes  071737271  (var-  inanni).  Last 
two  pairs  of  coxae  laterally  armed. 

Anal  and  penult  legs  short  and  but  moderately  thickened  in  female. 
In  the  male  the  fourth  joint  has  the  usual  ridge-like  elevation  along 
mesodorsal  surface,  this  increasing  in  height  proximad  and  terminat- 
ing in  a  conspicuous  flattened  lobe  lying  oblique  to  the  rest  of  the 
ridge,  with  the  longitudinal  furrow  widest  and  deepest  just  caudad  of 
this  lobe;  the  rounded  summit  of  lobe  densely  clothed  with  short, 
straight,  fine  hairs  (Plate  9,  fig.  1). 

Claw  of  female  gonopods  moderate  in  size,  only  slightly  curved;  tri- 
partite, with  the  lobes  subacute,  the  middle  one  being  but  little  longer 
than  the  inner  or  dorsal,  the  outer,  or  ventral,  smallest.  Spines 
moderately  slender.  Outer  basal  spine  of  each  pair  a  little  longer  than 
the  inner;  in  ventral  view  sides  of  spines  subparallel  from  base  to  the 
acuminate  apical  portion  or  gently  incurved  between  these  limits; 
apical  portion  short  and  but  moderately  acute.  Mesal  side  of  first 
article  straight  and  parallel  with  that  of  other  gonopod  or  nearly  so. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  363 

Length  11-16  mm.  A  female  15.5  mm.  long  has  antennae  5.5  mm. 
and  anal  legs  5.25  mm.  long,  with  tenth  plate  1.97  mm.  wide. 

Pseudomaturus. —  Coloration  as  in  adult  or  but,  on  an  average,  a  little 
paler. 

Antennae  same  as  in  maturus. 

Ocelli  1  +  5,  6,  3,  1;  1  +  5,  5,  4,  2;  fourteen  to  eighteen  in  three 
or  four  series. 

Claw  of  female  gonopods  a  little  smaller  and  paler  but  otherwise  as 
in  the  maturus.  Spines  not  differing  but  bristles  somewhat  fewer. 

Coxal  pores  a  little  smaller  relatively:  3,  4,  4,  3. 

Length  9-11  mm. 

TYPE  LOCALITY. —  California:  Pacific  Grove. 

Taken  also  in  California  at  Monterey,  Carmel,  and  Stanford. 

This  is  a  very  common  species  in  the  woods  near  Monterey  and 
Pacific  Grove  where  it  is  found  under  fallen  logs  and  the  bark  of  the 


POKABIUS  PITOPHILUS  (Chamberlin). 
Plate  9,  fig.  4,  5. 

LithoUus  pitophilw,  Proc.  Acad.  nat.  sci.  Phil.,  1903,  55,  p.  157.     Chamberlin, 

Pomona  coll.  journ.  ent.,  1910,  2,  p.  373. 
Poabius  pitophilus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  5,  p.  153. 

DESCRIPTION. —  Brown  to  chestnut.  Head  somewhat  darker  with 
frontal  region  paler  than  region  caudad  of  suture.  Antennae  chestnut, 
rufous  at  tips.  Prosternum  brown  or  pale  chestnut,  with  the  prehen- 
sors  lighter.  Venter  testaceous,  the  caudal  plates  darker  as  usual. 
Legs  pale  brown,  the  posterior  pairs  light  distally. 

Body  in  types  7.3-7.5  times  longer  than  width  of  tenth  plate. 
"\Yidths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates  to 
each  other  as  32  :  31  :  33  :  38  :  38  or  39  :  36. 

Head  considerably  wider  than  long  (8  :  7).  Caudal  margin  widely 
and  considerably  incurved.  Of  about  uniform  width  in  region  be- 
tween breaks  and  eyes. 

Antennae  short,  reaching  fifth  segment;  articles  twenty,  short  and 
approximately  uniform. 

Ocelli  mostly  ,twelve  to  twenty  in  four,  or  occasionally  in  three, 
longitudinal  series:  e.g.,  1  +  5,  4,  2;  1  +  3,  5,  3,  4;  1  +  4,  5,  5,  4; 
1  +  4,  5,  4,  5;  1  +  5,  5,  5,  3.  Single  ocellus  much  largest.  Other 
ocelli  regular  in  form  and  arrangement,  with  the  most  ventral  smallest 
as  usual. 


364  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Prosternum  typically  about  1 .48  times  wider  than  long.  Distance  . 
between  chitinous  spots  2.7  times  width  at  level  of  bottom  of  median 
sinus;  4.4  times  the  dental  line.  Sinus  widely  v-shaped  and  rather 
shallow,  its  sides  a  little  concave.  Teeth  small,  the  inner  one  on  each 
side  distinctly  and  considerably  larger  than  the  outer  and  the  line  of 
apices  thus  straight  or  sometimes  even  somewhat  procurved.  Spine 
small  and  slender. 

First  dorsal  plate  about  1.75  times  wider  than  long;  sides  but 
moderately  excurved  and  converging  caudad.  Posterior  minor 
plates  with  caudal  corners  abruptly  rounded,  not  excised. 

Coxal  pores  small,  circular:  3,  4,  4,  4;  4,  4,  5,  4;  4,  5,  5,  4;  4,  5,  5,  5. 

Spines  of  first  legs,  J  J 1 1 1  or  J-gHHri;  of  the  second  to  ninth,  J-^JJI; 
of  the  tenth,  £-J-|-||;  of  the  eleventh,  J °;  ]; M  or  J;iH;  37!;  of  the  twelfth 
and  thirteenth,  I'll'l'};  of  the  penult,  oHnri  claws  three;  of  the 
anal,  HiKo  or  5;^;H  daw  one. 

Anal  legs  of  male  short  with  the  fourth  joint  moderately  inflated. 
This  joint  dorsally  with  the  usual  conspicuous,  longitudinal,  ridge-like 
elevation  which  is  much  highest  at  beginning  of  middle  third  of  length 
of  article  where  it  is  produced  dorsad  or  mesodorsad  into  a  rounded 
lobe  between  which  and  the  anterior  end  the  ridge  is  lowest ;  at  caudal 
end  the  ridge  is  produced  into  a  small,  subconic  process  which  extends 
dorsocaudad.  Penult  legs  rather  slender,  weakly  longitudinally 
furrowed  above. 

Claw  of  female  gonopods  moderately  long  and  curved;  tripartite, 
with  the  lobes  rather  short  and  often  blunt,  or  sometimes  almost 
obliterated  and  leaving  the  claw  subentire.  Spines  short  and  rela- 
tively wide,  the  sides  somewhat  diverging  from  base  to  acuminate 
apical  portion  which  is  short  and,  especially  in  the  outer  spine,  ob- 
tusely angular  with  outer  slope  much  more  oblique  than  the  inner  and 
somewhat  crenulate;  inner  spine  inserted  farther  dorsad  so  that  in 
ventral  view  it  is  often  partly  covered  by  the  outer  one.  Mesal  sides 
of  first  article  of  the  two  gonopods  moderately  diverging  cephalad  but 
not  at  all  excavated. 

Gonopods  of  male  small,  sides  convex  and  strongly  converging  to  the 
short,  subtruncate,  distal  end  which  bears  in  an  indentation  a  very  stout 
bristle,  a  second  and  sometimes  a  third  smaller  bristle  also  present. 

Length  10-13  mm.  A  male  10.25  mm.  long  has  anal  legs  3.5  mm. 
long  and  tenth  plate  1.39  mm.  wide. 

TYPE  LOCALITY.—  California:  Truckee  (1902). 

The  types  were  taken  in  the  pine  woods  about  Truckee,  where  the 
species  is  common. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  365 

POKABIUS  IGINUS  (Chamberlin). 
Plate  8,  fig.  4;  Plate  10,  fig.  5. 
Poabius  iginus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  5,  p.  154. 

DESCRIPTION. —  Dorsum  brown,  the  posterior  plates  mostly  darker 
than  the  others;  in  some  the  major  plates  have  caudal  borders  dark- 
ened. Head  brown  of  dilute  ferruginous  cast  with  typically  a  dark, 
smoky,  or  blackish,  median  area  between  frontal  suture  and  caudal 
margin.  Antennae  similar  to  head  proximally,  becoming  paler  distad, 
the  ends  being  yellowish.  Prosternum  and  prehensors  similar  to 
head  but  lighter.  Venter  yellowish  to  dilute  brown,  the  last  few 
plates  much  darkest.  Legs  nearly  like  corresponding  plates  of  venter 
or  a  little  paler;  the  caudal  pairs  lightest  distally  as  usual.  , 

Typical  full  grown  males  average  near  7  times  longer  than  width  of 
tenth  plate  but  younger  males  and  females  are  more  slender,  being  as 
much  as  8.4  times  as  long  as  the  tenth  plate.  Widths  of  head  and  of 
first,  third,  eighth,  tenth  and  twelfth  plates  to  each  other  about  as 
39  :  39  :  41  :  45  :  45  :  43.5. 

Head  only  slightly  wider  than  long  (39  :  38).  Portion  back  of  eyes 
subquadrate,  the  sides  between  eyes  and  lateral  breaks  nearly  straight 
and  parallel,  from  breaks  rounding  about  corners  caudad  as  usual. 
Caudal  margin  straight.  A  transverse  sulcus  in  front  of  caudal 
margin  which  is  united  or  continuous  with  two  straight  longitudinal 
sulci  moderately  diverging  from  it  cephalad.  Hairs  short  and  sparse. 

Antennae  very  short,  reaching  only  to  the  fifth  segment,  attenuated 
distad  in  the  usual  degree.  Articles  twenty;  sides  of  each  article 
straight,  but  little  diverging  distad. 

Ocelli  twelve  to  fifteen  in  three,  or  sometimes  in  four,  series:  e.g., 
1  +  5,  5,  3,  a  common  arrangement;  1  +  5,  4,  3;  1  +  5,  5,  3,  1. 
Single  ocellus  of  moderate  size.  Ocelli  of  series  small  and  nearly 
uniform,  compact,  black. 

Prosternum  1.53  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.85  times  width  at  sinus;  4.6  times  dental  line.  Sinus 
rather  wide,  sides  a  little  concave.  Teeth  small ;  line  of  apices  a  little 
recurved.  Spine  short  and  slender,  not  bristle-like. 

First  plate  1.85  times  wider  than  long;  sides  straight  and  only 
slightly  converging  caudad.  Plates  smooth  or  under  lens  appearing 
only  slightly  obscurely  and  finely  roughened.  Caudal  margins  of  all 
plates  straight,  the  caudal  corners  simply  rounded  or  subrectangular. 


366  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Coxal  pores  very  small  or  minute,  circular:  2,  3,  4,  2;  2,  4,  3,  2; 
2,  3,  3,  2;  3,  4,  4,  3. 

Spines  of  first  legs,  SKHHH  to  070737!;  °f  the  second  to  eleventh, 
fHHHH;  of  the  twelfth,  %°VAV;  of  the  thirteenth  and  penult,  J;  J  J-J-|; 
of  the  anal,  0717!  270  >  claw  one.  Last  two  pairs  of  coxae  laterally  armed. 

In  the  anal  legs  of  male  the  third  joint,  or  prefemur,  is  strongly 
clavately  thickened  distad  but  is  not  extended  mesad  in  a  special 
lobe  as  in  most  related  species,  and  the  conical  process  is  only  ob- 
scurely, or  not  at  all,  indicated.  The  fourth  joint  bears  a  little  caudad 
of  its  anterior  end  the  usual  conspicuous  lobe  extending  in  a  meso- 
dorsal  direction,  but  this  is  smaller  than  usual  and  its  caudal  slope  is 
steeper  and  shorter,  the  usual  ridge-like  caudal  extension  of  the  eleva- 
tion absent  or  but  obscurely  indicated  but  the  process  at  the  caudal 
end  of  the  joint  is  well  developed,  subcylindric,  bearing  a  few  aculeate 
hairs,  a  small  number  of  which  also  occur  on  the  main  lobe.  Third, 
fourth,  and  fifth  articles  longitudinally  sulcate  dorsally,  the  sulcus  of 
the  fourth  lying  ectad  of  the  process  (Plate  8,  fig.  4).  Corresponding 
joints  of  the  penult  legs  also  similarly  sulcate. 

Claw  of  female  gonopods  very  short  and  relatively  broad,  thin  and 
nearly  straight;  tripartite,  the  lobes  rather  obtuse  and  distally  more 
or  less  rounded,  the  median  but  little  longer  than  the  others.  Basal 
spines  short  and  stout,  in  surface  view  with  sides  parallel  or  a  little 
diverging  distad  to  the  acutely  pointed  apical  portion,  broad  surface  of 
inner  spine  nearly  at  right  angles  with  that  of  the  outer  one  (Plate  10, 
fig.  5).  Inner  sides  of  first  article  of  the  two  gonopods  a  little  diverging 
from  each  other  cephalad  as  usual. 

Gonopods  of  male  very  short;  distally  bearing  a  bristle  which  arises 
from  a  slight  indentation,  no  other  bristles  being  observed  in  type. 

Length  of  types  11-12  mm.  A  male  11.5  mm.  long  has  antennae  5 
mm.  long  and  anal  leg  4.5  mm.  long,  the  tenth  plate  being  1 .64  mm.  wide. 

Pseudomaturus. —  Coloration  as  in  maturus  or  a  little  paler. 

Specimens  studied  considerably  more  slender  than  the  typical 
adults,  being  near  8.5  times  longer  than  width  of  tenth  plate. 

Antennae  as  in  maturus. 

Ocelli  1  +  4,  5,  3;  1  +  3,  4,  3;  1  +  3,  4,  2. 

Coxal  pores:  2,  3,  3,  2,  minute. 

Specimens  of  this  stage  studied  cannot  be  separated  on  basis  of 
length  from  the  true  maturus,  being  10-11.5  mm.  long. 

TYPE  LOCALITY. —  Washington  (E.  Bergroth). 

This  species  seems  to  be  nearest  to  P.  pitophilus,  which  it  probably 
replaces  in  the  north. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  367 


POKABIUS  CARINIPES  (Daday). 

LithoUus  carinipes  Daday,  Term,  fiigetek.,  1889,  12,  p.  153,  pi.  5,  fig.  31. 
Chamberlin,  Pomona  coll.  journ.  ent.,  1910,  2,  p.  372. 

The  original  description,  somewhat  rearranged,  is  as  follows:  — 

Brunneo,  medio  dorsi  fusco  fasciato. 

Corpore  gracili. 

Antennis  sat  longis,  22-  articulatis,  dense  crinitis,  in  apice  violaceis. 

Oculis  utrinque  15  in  seriebus  tribus  positis. 

Coxis  pedum  maxillarium  4-dentatis. 

Laminis  dorsalibus  inermibus,  sparsim  ciliatis. 

Poris  coxalibus  uniseriatis  2,  3,  4,  3. 

Pedibus  analibus  [maris]  sat  crassis,  articulo  tertio  quartoque  supra 
sulcatis,  articulo  tertio  sulco  profundiore  carinaque  in  apicem  rotun- 
data  aculeataque  instructo. 

Ungue  pedum  analium  simplici;  calcaribus  0,  1,  3,  2,  0;  articulo 
primo  calcari  laterali  armato. 

Longit.  corp.  15  mm.     Latit.  corp.  2.5  mm. 

Femina  ignota. 

LOCALITY. —  Northern  California:    One  male  (Joanne  Vadona). 

The  type  is  in  the  National  Museum  at  Budapest.  It  will  probably 
be  found  that  the  process  referred  to  the  third  joint  of  the  anal  legs 
involves  also  a  contiguous  lobe  at  proximal  end  of  the  fourth  and  that 
the  species  is  a  true  Pokabius. 


LOPHOBIUS,  subgen.  nov. 
POKABIUS  socius  Chamberlin. 

Plate  12,  fig.  2. 
LithoUus  socius  Chamberlin,  Proc.  U.  S.  N.  M.,  1901,  24,  p.  23. 

DESCRIPTION. —  Dorsum  yellowish  brown  to  clear  brown,  some- 
times with  a  paler  median  longitudinal  line.  Head  of  same  shade  as 
dorsum  or  darker  brown,  sometimes  of  dilute  chestnut  cast,  frontal 
region  somewhat  paler.  Antennae  light  brown,  paler  distally. 
Prosternum  and  prehensors  dark  brown  or  dilute  chestnut.  Venter 
yellowish  brown,  the  posterior  plates  deeper  brown.  Legs  light  brown, 
the  posterior  pairs  darker  like  the  corresponding  plates  of  venter. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  80  :  73  :  74  :  85  :  85  :  84. 


BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


FIG.  9. —  Distribution  of  Lophobius. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  369 

Head  subcordate,  considerably  wider  than  long  (8  :  7).  Marginal 
breaks  slight  or  scarcely  evident.  Caudal  margin  widely  incurved. 

Antennae  short  as  usual,  reaching  fifth  or  sixth  segment.  Articles 
normally  twenty,  occasionally  up  to  twenty-five;  first  seven  to  twelve 
moderately  long,  the  others  short. 

Ocelli  thirteen  to  twenty-two,  mostly  in  four  series,  occasionally  in 
three  or  five:  e.g.,  1  +  5,  4,  3;  1  +  5/4,  3,  1;  1  +  5,  4,  3,  2;  1  +  5, 
5,  3,  2;  1  +  5,  5,  4,  3,  2.  Single  ocellus  much  the  largest.  Organ  of 
Tomosvary  well  separated  from  the  ocelli. 

Prosternum  proportionately  very  wide,  being  near  1.72  times  wider 
than  long.  Distance  between  chitinous  spots  2.1  times  width  at 
level  of  bottom  of  median  sinus;  4.9+  times  the  dental  line  which  is 
proportionately  very  short.  Teeth  small,  normally  2  +  2,  occa- 
sionally extra  ones  occurring.  Margin  extending  from  ectal  tooth 
almost  directly  ectad  for  a  considerable  distance  before  abruptly 
bending  back  caudad.  Sinus  rather  wide,  somewhat  v-shaped, 
narrowly  rounded  at  bottom. 

Sides  of  first  dorsal  plate  convex  at  ends  but  nearly  straight  be- 
tween, only  weakly  converging  caudad.  Posterior  angles  of  the 
eleventh  and  thirteenth  dorsal  plates  weakly  produced;  those  of  the 
ninth  straight  or  somewhat  excised. 

Coxal  pores  moderate  in  size  and  circular  or  sometimes  somewhat 
transversely  oval:  3,  4,  4,  3;  4,  5,  5,  4;  5,  6,  6,  5. 

Spines  of  first  pair  of  legs,  o/itH  less  commonly  JiHHH;  of  the 
second,  oriHH;  of  the  third  to  eighth,  Jo; IB;  of  the  ninth  to  tenth, 
?o.°3.\V;  'of  the  eleventh,  J-^JI;  of  the  twelfth,  oio'J'JJ;  of  the  thir- 
teenth and  penult,  ^  °;  1 3;  \,  claws  three;  of  the  anal,  J;  i\  I'^j,  claws  two, 
the  accessory  claw  small. 

Anal  legs  of  male  rather  slender;  the  fourth  joint  a  little  clavate, 
with  a  distinct  dorsal  longitudinal  furrow  mesad  of  which  the  joint 
is  commonly  a  little  thickened  or  elevated  in  ridge-like  form,  this 
highest  at  caudal  end  but  not  truly  lobate  or  cristate. 

Claw  of  female  gonopods  short  and  broad,  tripartite,  with  lobes 
acute  or  rarely  with  four  or  five  more  obtuse  teeth  or  crenulations 
while,  in  the  other  direction,  one  of  the  three  lobes  normally  present 
may  be  obsolescent.  Spines  broad,  with  sides  more  or  less  diverging 
from  base  to  beginning  of  the  acuminate  portion  (Plate  12,  fig.  2). 

Length  12-14  mm. ;  of  anal  legs  5-5.6  mm. 

TYPE  LOCALITY.—  U.  S.  N.  M.  No.  784.    Utah :  near  Salt  Lake  City. 

Found  also  in  Utah  at  various  points  in  Salt  Lake,  Davis,  and  Utah 
counties. 


370  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

Under  stones  in  hollows  and  gulches  over  the  foothills  and  in  lower 
portions  of  canyons.  Often  in  association  with  P.  collium. 

POKABIUS  COLLIUM  (Chamberlin) . 
Plate  11,  fig.  4-6. 

Lithobius  collium  Chamberlin,  Proc.  U.  S.  N.  M.,  1901,  24,  p.  23. 
Nadabius  collium  Chamberlin,  Bull.  M.  C.  Z.,  1913,  57,  p.  62. 

DESCRIPTION. —  Yellow  to  light  brown,  or,  more  commonly,  with  a 
decided  tendency  to  ferruginous  or  orange;  in  some  part  of  plates  may 
be  dusky.  Head  sometimes  like  dorsum  but  more  typically  a  brighter 
lemon-yellow,  or  more  reddish  orange,  or  light  ferruginous.  Antennae 
mostly  bright  yellow  or  orange  proximally. 

Body  in  most,  slender  and  8.5-9  times  longer  than  width  of  tenth 
plate.  Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth 
plates  to  each  other  as  39  :  37  :  38  : 45  :  45  :  44. 

Head  wider  than  long  in  ratio  (average)  of  39  : 36.5.  Sides  only 
slightly  excurved  between  eyes  and  marginal  breaks,  which  are  weak 
or  obscure,  and  the  diameter  over  this  region  nearly  uniform.  Caudal 
margin  weakly  widely  incurved.  A  distinct  transverse  sulcus  in  front 
of  median  portion  of  caudal  margining  rim  with  two  sublongitudinal 
sulci  diverging  cephalad  from  this.  A  median  longitudinal  sulcus  as 
usual  in  front  of  suture. 

Antennae  short,  reaching  only  to  the  fifth  segment.  Strongly 
attenuated  distad,  the  tips  being  very  slender.  Articles  normally 
twenty,  sometimes  up  to  twenty-three,  short,  decreasing  distad. 

Ocelli  mostly  fifteen  to  twenty-two  in  number;  arranged  mostly  in 
four  series:  e.g.,  1  +  5,  5,  5,  3;  1  +  5,  5,  3,  1. 

Prosternum  1.45  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.64  times  greater  than  width  at  level  of  bottom  of  median 
sinus  and  5.38  times  the  dental  line  which  is  thus  proportionately  very 
short.  Median  sinus  rather  shallow  and  narrow,  well  rounded  at  the 
bottom.  Spine  small,  slender  and  hair  like.  Teeth  small;  line  of 
apices  recurved;  in  some  the  teeth  may  be  in  part  almost  obsolete 
(Plate  11,  fig.  4). 

First  dorsal  plate  1.7—  times  wider  than  long;  sides  convex,  con- 
verging caudad  of  anterior  third.  Caudal  corners  of  ninth,  eleventh, 
and  thirteenth  dorsal  plates  obliquely  excised.  Smooth. 

Coxal  pores  small,  the  most  proximal  one  on  each  coxa  often  minute 
and  the  most  distal  one  much  largest:  2,3,3,2;  3,4,4,3;  3,4,4,4. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  371 


Spines  of  first  and  second  legs,  [HHrH  or  <t  o'A  I'  1;  of  the  third  to 
eleventh,  J-J-J  J  \;  of  the  twelfth  and  thirteenth,  ftft  J-^J  of  the  penult, 
O&Hi  claws  three;  the  anterior  accessory  comparatively  long;  of 
the  anal,  J;  i',  I',  I',  o,  claw  one.  Last  three  pairs  of  coxae  laterally  armed. 

Anal  legs  short;  slender  distad  of  the  fourth  article  which  is  thick- 
ened; fourth  article  clavately  widening  distad,  considerably  thicker  in 
dorsoventral  direction  than  in  lateral,  dorsally  with  a  conspicuous 
ridge-like  elevation  which,  beginning  even  with  the  general  surface 
at  the  proximal  end,  rises  in  height  to  the  caudal  end  where  it  termi- 
nates as  a  somewhat  rounded  prominence  or  crest,  which  is  toward  the 
mesal  side  and  projects  dorsomesad,  the  ridge  curving  somewhat 
mesad  of  directly  caudad  in  its  course  from  anterior  to  posterior  end, 
the  joint  longitudinally  furrowed  mesad  of  the  ridge  (Plate  11,  fig.  6). 

Gonopods  of  male  small  and  rounded,  wart-like,  each  bearing  dis- 
tally  two  long  bristles. 

Claw  of  female  gonopods  of  moderate  length,  considerably  curved; 
tripartite,  the  three  lobes  typically  distinct  with  the  median  largest, 
but  claw  occasionally  subentire.  Spines  moderately  stout,  the  outer 
a  little  the  larger;  in  view  of  broader  surface  the  sides  are  subparallel 
or  slightly  divergent  to  the  acutely  acuminate  apical  portion  (Plate  11, 
fig.  5). 

Length  13-16  mm.  A  male  15  mm.  long  has  antennae  5.5  mm.  and 
anal  leg  about  4.7  mm.  long  with  the  tenth  plate  1.64  mm.  wide. 

Pseudomaturus.  —  Coloration  as  in  adult  or  a  lighter  yellow.  Head, 
antennae,  and  posterior  legs  lemon-yellow. 

Gonopods  of  female  w^ith  claw  nearly  as  in  adult  or  a  little  thinner. 
Spines  slightly  more  slender,  with  the  inner  one  sometimes  relatively 
somewhat  smaller. 

Dorsal  spines  of  first  legs  mostly,  0,0,2,2,1.  Ventral  spines  of 
twelfth  and  thirteenth  legs  more  commonly  0,  0,  2,  3,  2. 

Anal  legs  of  male  as  in  maturus  but  ridge  and  crest  a  little  less  pro- 
nounced. 

Length  10-12  mm. 

Pracmaturus.  —  Yellow,  head  and  posterior  plates  brightest. 

Ocelli  1  +  4,  3,  1  ;  1  +  4,  3,  2.  Ocelli  well  separated,  first  of  top 
series  large. 

Coxal  pores:  2,  3,  3,  2,  minute. 

Claw  of  female  gonopods  with  claw  nearly  same  as  in  older  stages. 
Third  article  with  two  bristles,  second  with  three  or  four,  and  first  with 
four  to  six.  Spines  2  +  2,  the  inner  much  the  smaller,  close  together, 
acutely  acuminate  from  base. 


372  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 


legs,  07571;  M;   of  the  second,  0,0,11,1;  of  the  twelfth, 
irteenth,'  srJ-JJl;   of  anal  and  penult  as  in  adult. 


Spines  of  first 

;   of  the  thirteenth, 

Length  of  specimen  described  9.25  mm. 

Late  immaturus.—  Yellow  with  last  plates  and  the  head  brightest. 
Antennae  like  head.  Venter  paler.  Last  pair  of  legs  bright  yellow. 

Antennae  with  twenty  articles  which  are  short  and  closely  com- 
pacted. 

Ocelli  1  +  4,  3,  small,  well  separated,  the  single  ocellus  smaller  than 
first  one  of  upper  series. 

Prosternum  nearly  as  in  adult.  Line  of  apices  of  teeth  more  nearly 
straight.  1.48  times  wider  than  long.  Distance  between  chitinous 
spots  three  times  width  at  level  of  sinus;  4.3  times  the  dental  line. 
The  anterior  portion  proportionately  less  wide  than  in  adult  and  the 
dental  line  relatively  longer. 

Coxal  pores  minute:   2,  2,  2,  2. 

Gonopods  of  female  with  a  claw  present,  thin,  small,  acute  and  pale 
with  lateral  teeth  already  indicated.  Spines  1  +  1,  acute,  attenu- 
ated from  base  to  tip.  Second  article  with  two  bristles,  the  first  with 
three  or  four. 

Spining  as  given  for  praematurus,  which  is  early  in  that  stage  as  the 
present  is  late  in  the  immaturus. 

Length  9  mm.;  antennae  2.6  mm.;  arial  leg  2.9  mm.;  width  of 
tenth  plate  1  mm.  Widths  of  head  and  of  the  first,  eighth,  tenth 
and  twelfth  plates  to  each  other  as  47  :  43  :  46  :  55  :  55  :  53. 

TYPE.—  U.  S.  N.  M.  No  783.     Utah:  Salt  Lake  Co. 

Found  also  in  Utah  in  Salt  Lake  City,  Farmington,  Ogden,  Provo, 
Lake  Point,  Antelope  Island,  Fremont  Island,  etc. 

This  species  is  very  common  in  Utah  under  stones  over  the  foothills 
during  the  damper  months  in  spring  and  fall  and  in  the  lower  parts  of 
the  canyons.  It  was  found  comparatively  abundant  under  stones  on 
the  islands  of  the  Great  Salt  Lake. 

POKABIUS  PUNGONIUS  (Chamberlin)  . 
Sozibius  pungonius  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1912,  5,  p.  152. 

DESCRIPTION.  —  Dorsum  light  testaceous,  with  the  caudal  plates 
and  the  head  darker.  Antennae  yellow  proximally  and  at  tips,  the 
remaining  portion  somewhat  darker.  Prosternum  and  caudal  ventral 
plates  yellowish,  the  remaining  portion  of  venter  a  paler  yellow. 
Posterior  pairs  of  legs  bright  yellow. 

Body  of  type  8.6—  times  longer  than  width  of  tenth  plate.     Widths 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  373 

of  head  and  of  first,  third,  eighth,  and  tenth  plates  to  each  other  as 
33  :  30  :  35  :  35  :  34. 

Head  in  type  precisely  equal  in  length  and  breadth.  Caudal 
margin  straight.  Margination  distinct  and  continuous  cephalad  to 
eyes,  there  being  no  distinct  marginal  breaks  though  there  is  evident 
the  very  oblique  suture  through  the  marginal  rim.  Hairs  sparse 
and  moderately  long.  Punctae  irregular  and  weak. 

Each  antenna  in  type  composed  of  twenty-one  articles  of  which  all 
but  the  most  proximal  and  the  ultimate  are  very  short  and  closely 
united,  decreasing  distad.  Antennae  very  short,  reaching  the  fifth 
segment. 

Ocelli  twelve  to  fifteen  in  four  series:  e.g  ,  1  +  2,  4,  4,  4;  1  +  3,  4, 
3,  1.  Ocelli  small,  black,  irregular  in  form  and  size,  with  the  series  also 
irregular.  Single  ocellus  small  like  the  others. 

Prosternum  only  1.4  times  wider  than  long.  Distance  between 
chitinous  spots  2.65  times  as  great  as  width  at  level  of  bottom  of  sinus; 
4.24  times  length  of  dental  line.  Teeth  small,  black,  narrowly 
rounded  or  subacute  distally;  in  type  2  +  3;  line  of  apices  distinctly 
recurved.  Sinus  narrow,  sides  acutely  converging.  Spine  slender  and 
acute,  close  to  outer  tooth. 

First  dorsal  plate  1.66+  times  wider  than  long;  sides  rounded, 
conspicuously  narrowed  caudad  of  middle.  None  of  plates  with 
caudal  angles  produced.  Posterior  plates  weakly  finely  roughened 
and  punctate. 

Coxal  pores  very  small  or  minute:  3,  3,  3,  2. 

Spines  of  first  legs,  o  o'^'s  •>;  of  the  second  to  sixth,  o'o'^M;  of  the 
seventh,  0°;  J  |  jjj  or  J-J  |f|; '  of  the  eighth  to  eleventh,  0°;  J-J  £|;  of  the 
twelfth  and  thirteenth,  J;  o,  |  £  2!  of  the  penult,  oTirHri  tne  c^aw  one  or 
accessory  claw  obsolescent;  of  the  anal,  JJJ£-$,  claw  one.  Last  two 
pairs  of  coxae  laterally  armed. 

Anal  legs  of  male  short  and  slender,  not  at  all  specially  modified. 

Gonopods  of  male  pale,  rounded,  bearing  two  bristles. 

Length  11  mm.;  antennae  and  anal  legs  4  mm.;  width  of  tenth 
plate  1.28  mm. 

TYPE  LOCALITY.— Colorado:   Marshall  (T.  D.  A.  Cockerell). 

Only  the  male  of  this  interesting  species  is  known. 

POKABIUS   ARIZONAE,    sp.    nov. 

DESCRIPTION. —  Light  orange-yellow  with  the  head  and  the  poste- 
rior plates  a  deeper  orange,  the  frontal  region  of  head  palest.  An- 
tennae like  head  but  lighter  yellow  distad.  Prosternum  and  pre- 


374  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

hensors  light  orange.  Legs  yellow,  the  posterior  pairs  more  brightly 
pigmented,  light  orange. 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  61  :  56  :  58  :  65  :  67  :  62. 

Head  in  type  slightly  longer  than  wide  (63  :  61).  Rather  strongly 
narrowed  cephalad.  Marginal  breaks  weak,  oblique.  Caudal  margin 
weakly  widely  incurved. 

Antennae  short.  Articles  twenty-four;  first  four  moderately  long, 
the  others  decreasing  gradually  distad;  ultimate  shorter  than  the  two 
preceding  ones  taken  together. 

Ocelli  1  +  4,  4,  2.     Single  ocellus  largest  though  not  greatly  so. 

Prosternum  1.55  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.68  times  width  at  level  of  sinus;  4.25  times  dental  line. 
Teeth  apically  narrowly  rounded;  distance  between  teeth  of  each 
pair  about  equal  to  that  between  the  two  mesal  ones.  Sinus  broadly 
v-shaped,  the  sides  straight.  Spine  clearly  stouter  than  the  bristles, 
straight,  regularly  acutely  acuminate. 

First  dorsal  plate  widest  a  little  cephalad  of  middle,  not  strongly 
narrowed  caudad;  1 .6  times  wider  than  long.  Posterior  corners  of  the 
ninth,  eleventh,  and  thirteenth  dorsal  plates  obliquely  excised. 

Coxal  pores  small,  widely  separated:   2,  2,  3,  2. 

Spines  of  first  to  fourth  pairs  of  legs,  "'  Q' I'll',  of  the  fifth  to  eleventh, 
mtl;  of  the  twelfth,  H£H  or  j^;'  of  the  thirteenth,  J$f£J; 
of  the  penult,  JixlH'  claws  three,  with  the  accessory  claws  small  but 
distinct. 

Anal  legs  of  male  slender,  not  modified. 

Gonopods  of  male  well  exposed;  bearing  two  bristles. 

Length  12  mm. 

TYPE.— M.  C.  Z.,  No.  285,  Arizona:  Tucson  (W.  M.  Wheeler). 

This  species  is  known  from  a  single  male.     It  is  aberrant. 


POKABIUS   HELENAE,    Sp.    nOV. 

Plate  12,  fig.  3. 

DESCRIPTION. —  Dorsum  yellowish  brown  to  clear  brown,  with 
sometimes  part  of  the  plates  dusky.  Head  mostly  more  or  less 
ferruginous  with  frontal  region  a  little  paler.  Prosternum  and  pre- 
hensors  testaceous  of  a  dilute  ferruginous  tinge.  Venter  yellow  to 
yellowish  brown,  with  caudal  plates  ferruginous.  Legs  like  corre- 
sponding plates  of  venter. 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  375 

Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth  plates 
to  each  other  as  76  :  72  :  74  :  85  :  86  :  84. 

Head  widest  immediately  caudad  of  eyes,  a  little  wider  than  long. 
Caudal  margin  mesally  incurved.  Marginal  breaks  slight. 

Antennae  short  and  slender,  usually  reaching  to  the  fifth  segment. 
Articles  normally  twenty,  moderate,  sometimes  the  first  seven  to  ten 
markedly  and  abruptly  longer  than  those  succeeding.  Ultimate 
article  longer  than  the  two  preceding  together. 

Ocelli  fifteen  to  eighteen  in  three  or  more  frequently  in  four  series: 
e.g.,  1  +  5,  5,  4;  1  +  5,  4,  4,  3;  1  +  5,  5,  3,  2;  1  +  5,  5,  4,  2;  1  +  5, 
6,  5,  1 ;  1  +  6,  5,  4,  2.  Single  ocellus  clearly  largest,  elliptic.  Organ 
of  Tomosvary  relatively  small. 

Prosternum  1.65  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.5  times  width  at  level  of  sinus;  4.33+  times  the  dental 
line.  Sides  of  anterior  portion  convex  and  rounding  out  considerably 
laterad.  Teeth  very  small,  narrow  at  base,  distally  rounded.  Sinus 
strictly  v-shaped.  Spines  slender,  distally  bristle-like,  straight  or 
nearly  so. 

First  dorsal  plate  a  little  widest  anteriorly;  sides  substraight  and 
not  strongly  converging  caudad  to  the  rounded  posterior  corners;  in 
type  near  1.9  times  wider  than  long.  Posterior  corners  of  the  thir- 
teenth plate  weakly  produced,  those  of  the  ninth  and  eleventh  typi- 
cally, somewhat  concavely,  excised. 

Coxal  pores:  3,4,4,3;  4,4,4,4;  4,5,5,3;  4,5,5,4;  etc. 

Spines  of  first  legs,  0023-2;  of  the  third  to  ninth,  J^fff;  of  the 
tenth,  KJH;  of  the 'eleventh,  JJ-JH;  of  the  twelfth,  %$$£%  or 
t ":  I', 1\  1;  of  the  thirteenth  and  penult,  oTiriBri  claws  three;  of  the  anal, 
oHHrO'  c^aw  one-  Last  two  Pairs  °f  coxa  laterally  armed  or  spine  of 
penult  coxae  sometimes  absent. 

Anal  legs  of  male  rather  slender;  the  fourth  joint  a  little  crassate, 
a  little  incurved  or  depressed  above  and  weakly  elevated  at  distal  end. 

Claw  of  female  gonopods  short,  tripartite,  the  lobes  all  acute  and 
distinct,  the  median  longest  though  not  greatly  so.  Spines  moder- 
ately long  and  of  moderate  proportionate  breadth,  sometimes  appear- 
ing bent  mesad  near  middle  of  length,  the  sides  typically  subparallel 
from  base  to  apical  portion. 

Length  9-13  mm. 

TYPE.— M   C.  Z.,  No.  185.    Montana:    Helena  (W.  M.  Mann). 


376  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

POKABIUS  CASTELLOPES  (Chamberlin) . 
Plate  12,  fig.  1. 

LithoUus  castellopes  Chamberlin,  Proc.  Acad.  nat.  sci.  Phil.,  1903,  55,  p.  158. 
Pomona  coll.  journ.  ent.,  1910,  2,  p.  373. 

DESCRIPTION. —  Dorsum  testaceous;  head  but  little  paler.  An- 
tennae light;  paler  distad  than  proximad.  Legs  yellowish,  the 
caudal  pairs  more  deeply  pigmented  and  brown  proximad,  yellowish 
distad. 

Body  in  type  7  times,  or  a  little  less,  longer  than  width  of  tenth 
plate.  Widths  of  head  and  of  first,  third,  eighth,  tenth,  and  twelfth 
plates  to  each  other  as  28  :  26  :  27.5  :  32  :  35  :  33. 

Head  a  little  longer  than  wide  (30  : 28.5).  Cordate.  Caudal 
margin  mesally  incurved.  Head  considerably  narrowed  cephalad. 
Sparsely  clothed  with  rather  long  hairs.  Smooth.  Marginal  breaks 
distinct. 

Antennae  short;  slender  distad.  Articles  short  and  very  short, 
decreasing  distad  as  usual. 

Ocelli  twelve  in  three  series:  1  +  5,  4,  2.  Patch  elongate.  Ocelli 
separated,  not  contiguous,  those  of  top  series  considerably  largest. 

Prosternum  1.4  times  wider  than  long.  Distance  between  chitin- 
ous  spots  2.38  times  greater  than  width  at  level  of  bottom  of  median 
sinus;  3.58  times  the  dental  line.  Median  sinus  strictly  v-shaped, 
with  sides  straight.  Teeth  small  and  pale;  line  of  apices  recurved. 

First  dorsal  plate  1.8  times  wider  than  long,  widest  anteriorly  and 
considerably  narrowed  caudad.  Caudal  minor  plates  with  posterior 
corners  obliquely  excised,  but  line  of  excision  short.  Smooth. 

Coxal  pores  very  small :  2,  3,  3,  2. 

Spines  of  first  to  third  pairs  of  legs,  o' L-f-f  \;  of  the  fourth  to  eleventh, 
oHHH;  of  the  twelfth,  yHHK;  of 'the 'thirteenth,  fcJ-J-Ji;  of  the 
penult,  oTiHB;  i>  claws  three;  of  the  anal,  STILTS,  claw  one.  Last  two 
pairs  of  coxae  laterally  armed. 

Anal  and  penult  legs  in  the  male  considerably  swollen.  Anal  legs 
short;  fourth  joint  thick,  somewhat  bowed  ventrad  with  dorsal 
surface  concave,  saddle-like  and  at  distal  end  elevated  into  a  con- 
spicuous lobe  which  narrows  to  an  edge  dorsad  and  is  truncate  caudad 
on  level  with  end  of  joint  or  distally  a  little  extending  beyond  it;  lobe 
on  caudal  surface  near  apex  bearing  a  caudally  directed  spine;  dorsal 
surface  of  joint  cephalad  of  the  lobe  longitudinally  sulcate  (Plate  12, 
fig.  1). 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  377 

Gonopods  of  male  well  exposed;  distally  truncate;  sides  sub- 
parallel. 

Length  of  type  (cf )  8.8  mm.;  antennae  and  anal  legs  3  mm.;  tenth 
plate  cir.  1.28  mm.  wide. 

TYPE  LOCALITY. — •  California:  Shasta  Springs  (1902). 


POKABIUS   EREMUS,    Sp.    nOV. 

DESCRIPTION. —  Brown,  with  the  head  darkest.  Antennae  light 
brown.  Venter  light  brown.  Legs  pale,  posterior  pairs  darker,  light 
distally. 

Body  moderately  narrowed  cephalad  from  the  tenth  plate  with  the 
first  dorsal  plate  slightly  narrower  than  the  third  and  much  narrower 
than  the  head.  Widths  of  head  and  of  first,  third,  eighth,  tenth,  and 
twelfth  plates  to  each  other  as  57  :  50  :  51  :  62  :  64  :  64. 

Head  slightly  wider  than  long  (57  :  56  or  55).  Widest  a  little 
caudad  of  eyes  from  where  narrowing  regularly  to  the  caudal  corners, 
a  little  indented  or  incurved  at  level  of  suture  where  the  marginal 
break  would  be  if  present.  Caudal  margin  straight.  Conspicuously 
narrowed  cephalad. 

Antennae  of  intermediate  length,  reaching  to  sixth  segment. 
Articles  twenty  to  twenty-one,  of  intermediate  length  to  rather  long, 
subcylindric,  each  only  slightly  widening  distad,  of  nearly  uniform 
proportions;  ultimate  shorter  than  the  two  preceding  ones  taken 
together. 

Ocelli  in  type  twelve  in  three  series:  1  +  5,  4,  2.  Those  of  the 
upper  series  large,  regular,  deeply  pigmented.  Single  ocellus  not 
larger  than  the  caudal  ones  of  series,  or  but  little  so,  and  not  otherwise 
sharply  differentiated.  Ocelli  of  most  ventral  series  considerably 
smaller  and  paler  than  the  others  in  the  type. 

Prosternum  in  type  1.425  times  wider  than  long.  Distance  between 
chitinous  spots  2.8  times  width  at  level  of  bottom  of  median  incision; 
4.5  times  length  of  dental  line,  the  anterior  portion  of  the  prosternum 
being  especially  narrow  at  its  cephalic  end  and  the  dental  line  corre- 
spondingly short.  Median  incision  large;  sides  concave;  narrowly 
rounded  at  bottom;  wide,  the  distance  between  inner  teeth  being 
greater  than  that  between  the  teeth  of  each  pair.  Spine  rather  stout 
at  base;  long  and  slenderly  acuminate;  inserted  a  considerable  dis- 
tance caudad  of  level  of  teeth.  Margin  sloping  directly  ectocaudad 
from  base  of  outer  tooth. 


378  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

First  dorsal  plate  with  sides  only  weakly  convex,  regularly  and  only 
moderately  converging  caudad;  in  type  dr.  1.78  times  wider  than 
long.  Posterior  corners  of  ninth,  eleventh,  and  thirteenth  dorsal 
plates  obliquely  excised  (the  right  corner  of  ninth  plate  in  type  is  not 
thus  excised)  but  the  caudal  margin  is  a  little  angularly  extended 
caudad  just  mesad  of  inner  end  of  the  excision. 

Coxal  pores  small,  especially  so  the  proximal  ones:  4,  4,  4,  5. 

Spines  of  first  legs,  ^  £  l\\;  of  the  second  to  seventh,  oMriHri;  of  the 
eighth  and  ninth,  tfffi»  of  the  tenth>  KlrK  or  Jo,' III;  of  the 
eleventh,  fcJJil;  of  the  twelfth,  otHrH  or  K I', I', \\  of  the  thirteenth, 
HHrH;  of  the  penult,  o7irl~H>  claws  three,  the  anterior  accessory 
being  long  and  slender;  of  the  anal,  orHrH'  the  claw  single.  Last 
two  pairs  of  coxae  laterally  armed. 

Claw  of  female  gonopods  long  and  rather  slender,  strongly  curved; 
tripartite,  with  the  lobes  all  acute  and  the  median  not  greatly  exceed- 
ing the  lateral  ones.  In  ventral  view  the  outer  basal  spine  is  narrowest 
near  the  middle,  the  sides  incurving;  the  acuminate  apical  portion  is 
very  short,  with  one  or  both  edges  denticulate  and  the  tip  truncate. 
The  outer  spine  is  larger  than  the  inner  one  which  appears  acuminate 
from  very  base  and  is  distally  acute. 

Length  of  type  ( 9  ),  8.5  mm. 

TYPE.— M.  C.  Z.,  No.  187.     British  Columbia:   Kaslo. 

The  spining  of  the  legs  of  this  species  at  once  differentiates  it  from 
the  others  at  present  known.  It  is  the  only  one  in  which  the  tibia  of 
the  anterior  legs  bears  two  dorsal  spines,  and  in  which  the  tibia  of  the 
penult  leg  is  armed  dorsally. 

SIMOBIUS  gen.  nov. 

Marginal  interruptions  of  head  slight  and  oblique  or  sometimes 
scarcely  manifest. 

Antennae  short ;  composed  in  type  species  of  twenty-one  or  twenty- 
two  articles. 

Eyes  composed  of  seriate  ocelli;  single  ocellus  distinctly  differen- 
tiated, large. 

Prosternal  teeth  2  +  2;  line  of  apices  recurved.  Spines  slender, 
bristle-like. 

Posterior  corners  of  llth  and  13th  plates  (in  type-species)  weakly 
produced. 

Coxal  pores  small,  circular;  uniseriate. 

Claw  of  female  gonopods  tripartite,  the  median  tooth  not  much 


CHAMBERLIN:  NORTH  AMERICAN  LITHOBIIDAE.  379 


FIG.    10.—  Distribution  of  Simobius. 


380  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

exceeding  the  lateral  ones.  Spines  2  +  2,  of  intermediate  length  and 
breadth.  First  article  of  gonopods  not  excavated  proximally. 

Tarsi  of  anterior  legs  divided. 

Anal  legs  of  male  short  and  moderately  inflated;  without  special 
processes  or  modifications.  Penult  legs  in  male  with  fifth  article 
bearing  at  the  distal  end  on  the  dorsal  surface  a  conspicuous  process. 

Last  two  pairs  of  coxae  laterally  armed.  Third  joint  of  all  legs 
caudad  of  the  second  pair  normally  with  three  spines.  Fifth  joint  of 
all  legs  between  first  or  second  and  twelfth  with  two  dorsal  spines. 
In  type  species,  dorsal  spines  of  anal  legs  1,  0,  3,  1,0;  ventral,  0,  1, 
3,  3,  1;  claw  single.  Dorsal  spines  of  penult  legs  1,0,  3,  1,  0;  ventral 
0,  1,  3,  3,  2;  claws  three.  Dorsal  spines  of  twelfth  legs  1,  0,  3,  1,  2; 
ventral  0,  0,  3,  3,  2. 

Length  1 1  mm.  and  over. 

TYPE. —  S.  ginampus  (Chamberlin). 

The  type  species  is  the  only  one  thus  far  known.  In  the  character 
of  the  modification  of  the  penult  leg  in  the  male,  the  genus  suggests 
Guambius  but  is  very  readily  distinguished  from  that  genus  in  other 
characters. 

SIMOBIUS  GINAMPUS  (Chamberlin). 

Plate  12,  fig.  4,  5. 
Lithobius  ginampus  Chamberlin,  Ann.  Ent.  soc.  Amer.,  1911,  1909,  2,  p.  187. 

DESCRIPTION. —  Dorsum  yellowish  brown  or  testaceous  to  dark 
smoky  brown,  or  somewhat  mahogany-brown,  when  in  full  color  show- 
ing a  longitudinal  darker  stripe  on  all  or  most  of  the  major  plates. 
Head  from  light  chestnut,  in  paler  specimens,  to  mahogany  or  almost 
black  in  the  darker  ones.  Antennae  light  brown  to  chestnut  proxi- 
mally, paler  distally  Prosternum  from  light  brown  to  dark  smoky 
brown;  prehensors  lighter,  rufous,  distad.  Venter  yellowish  to  brown, 
the  last  several  plates  darker.  Legs  yellowish  to  brown,  nearly  uni- 
form. 

Body  proportionately  wide,  being  commonly  only  7,  or  less,  times 
longer  than  width  of  the  tenth  plate.  Body  considerably  narrowed 
cephalad  with  the  first  plate  narrower  than  the  head  and  than  the 
third,  the  latter  being  but  little  narrower  than  the  head.  Widths  of 
head  and  of  first,  third,  eighth,  and  tenth  plates  to  each  other  as  48  : 
45  :  47  :  55  :  50. 

Head  wider  than  long  in  about  the  ratio  48  :  45.     Rather  strongly 


CHAMBERLIX:   NORTH   AMERICAN   LITHOBIIDAE.  381 

narrowed  cephalad  from  caudal  edge  of  eyes.  Immediately  in  front 
of  the  suture  is  a  median  depression  and  a  little  in  front  of  this  a  dot- 
like  second  impression;  immediately  caudad  of  the  suture  is  a  dot-like 
impression  each  side  of  the  median  line  and  a  second  similar  pair 
farther  caudad;  the  usual  semicircular  impression  just  in  front  of  the 
caudal  margin.  Head  otherwise  nearly  smooth,  shining. 

Antennae  very  short;  reaching  fifth  or  sixth  segment.  Articles 
twenty-one  or  twenty-two,  short  and  subcylindric;  ultimate  rather 
long. 

Ocelli  of  each  eye  mostly  ten  or  twelve  in  three  series:  e.g.,  1  +  4, 
3, 2;  1  +  4, 4, 2;  1  +  4, 4, 3.  Single  ocellus  large,  ovate;  of  the  other 
ocelli,  the  most  caudal  of  the  dorsal  series  are  largest,  the  others 
decreasing  Cephalad  and  ventrad. 

First  dorsal  plate  near  1.8  times  wider  than  long.  Most  major 
plates  showing  a  pair  of  furrows  diverging  from  the  anterior  end 
caudad  and  the  usual  short,  transverse,  submarginal  sulcus  on  each 
side  near  beginning  of  caudal  third  of  length.  Moderately  rough- 
ened, the  caudal  plates  more  distinctly  so.  Posterior  angles  of  ninth 
plate  with  caudal  edge  straight  or  a  little  bent  cephalad;  those  of 
eleventh  and  thirteenth  a  little  produced  caudad. 

Ventral  plates  with  the  usual  three  longitudinal  sulci.  A  submedian 
transverse  impression  which  is  most  distinct  on  plates  toward  caudal 
end. 

Coxal  pores  small,  decreasing  proximad:  3,  4,  4,  3;  3,  4,  5,  3; 
4,  5,  4,  3;  4,  5,  5,  4;  etc. 

Spinesof  firstlegs,  JHKH4 or %%-* l\-  of thesecond,  J -J- J J| or  J-JJH; 
of  the  third  to  tenth,  J-J-J-J  \;  of  the  eleventh,  J-J-J  I  \\  of  the  twelfth, 
OTTO;!:  of  the  thirteenth,  HrlrH:  of  the  penult,  fctJH  claws  three; 
of  the  anal,  J; -$;•  \  j; --$,  claw  one.  Last  two  pairs  of  coxae  laterally  armed. 

Anal  and  penult  legs  of  male  short  and  moderately  inflated  with  the 
tibial  joints  abruptly  more  slender.  Anal  legs  without  special  lobes. 
Penult  legs  with  the  fifth  article  having  dorsocaudal  corner  of  distal 
end  obliquely  excised  as  in  Arenobius,  etc.,  and  bearing  upon  the 
oblique  surface  a  conspicuous  subcylindric  but  laterally  compressed, 
process  which  is  sublongitudinal  in  position  and  is  as  high,  or  nearly 
as  high,  at  proximal  as  at  distal  end;  free  surface  of  lobe  obliquely 
truncate,  bearing  but  few  bristles  (Plate  12,  fig.  4). 

Gonopods  of  male  well  exposed,  with  sides  convex  and  the  distal 
edge  oblique  and  nearly  straight,  the  ectal  side  being  shorter  than  the 
mesal;  bearing  two  bristles. 

Claw  of  female  gonopods  tripartite,  the  lobes  or  teeth  short  and 


382  BULLETIN:  MUSEUM  OF  COMPARATIVE  ZOOLOGY. 

usually  rather  blunt,  the  median  being  longest  though  not  greatly 
so.  Outer  spine  longer  than  the  inner;  a  little  acuminate  from  base 
distad  with  the  sides  more  or  less  incurved  near  the  middle;  apical 
portion  short,  narrowly  rounded  at  tip  (Plate  12,  fig.  5). 

Length  of  types  11  to  14  mm.  A  male  13.5  mm.  long  has  antennae 
5  mm.  long,  anal  legs  4  mm.  long,  and  the  tenth  plate  2  mm.  wide. 

TYPE  LOCALITY. —  Washington:  Pullman  (W.  M.  Mann). 

Found  also  in  Alaska  on  Forrester  Island  (Harold  and  R.  W.  Heath). 


PLATE  1. 


CHAMBEBLIN. —  Lithobiid  Genera. 


PLATE  1. 

Sozibius  pennsylvanicus  Chamberlin.     (Upsal,  Pa.). 

Fig.  1.  Fourth  joint  of  anal  leg,  mesal  view. 

Fig.  2.  Ocelli  of  right  eye  and  organ  of  Tomosvary,  showing  typical 
relations. 

Fig.  3.  Ocelli  of  left  eye  of  another  specimen,  showing  larger  actual  and 
relative  size  of  ocelli. 

Fig.  4.  Claw  of  gonopod  of  9  viewed  at  right  angles  to  its  concave  surface. 

Fig.  5.  Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

SoziUus  tuobukus  (Chamberlin).     (Hot  Springs,  N.  C.). 
Fig.  6.     Third  and  fourth  joints  of  right  anal  leg  of  cT,  dorsal  view. 


BULL.  MUS.  COMP.  ZOOL. 


LITHOBIIDAE.    PLATE  1 


6 


HELIOTYFE  CO.   BO6TC 


PLATE  2. 


CHAMBERLIN. —  Lithobiid  Genera. 


PLATE  2. 

Sozibius  tuobukus  (Chamberlin).     (Hot  Springs,  N.  C.). 

Fig.  1.     Claw  of  right  gonopod  of  9 ,  sub  ventral  view. 
Fig.  2.     Basal  spines  of  left  9  gonopod,  ventral  view. 

Sozibius  providens  (Bollman). 

Fig.  3.  Anterior  portion  of  prosternum.     (Russellville,  Tenn.), 

Fig.  4.  Claw  of  right  gonopod  of  9 ,  subventral  view.  (Russellville, 
Tenn.). 

Fig.  5.  Basal  spines  of  left  gonopod  of  9,  ventral  view.  (Russellville, 
Tenn.). 

Fig.  6.  Basal  spines  of  right  gonopod  of  9  .  (Type,  Bloomington,  Indiana, 
showing,  in  comparison  with  Fig.  5,  extent  of  variation  in  form). 


JLL.  MUS.  COMP.  ZOOL. 


LITHOBIIDAE.    PLATE  2 


6 


HELIOTYPE  CO.    BOSTC 


PLATE  3. 


CHAMBEHLIN. —  Lithobiid  Genera. 


PLATE  3. 

Pampibius  paitius  (Chamberlin).     (Unaka  Springs,  Tenn.). 

Fig.  1.  Anterior  portion  of  prosternum. 

Fig.  2.  Ocelli  of  left  eye  and  organ  of  Tomosvary. 

Fig.  3.  Third  and  fourth  joints  of  left  anal  leg  of  <f,  mesal  view. 

Fig.  4.  Basal  spines  of  right  gonopod  of  9 ,  subventral  view. 

Typhlobiiis  kebus  Chamberlin.     (Santa  Barbara,  Cal.). 

Fig.  5.     Anterior  portion  of  prosternum. 

Fig.  6.     Claw  of  right  gonopod  of  9 ,  subventral  view. 


Typhlobius  coecus  (Bollman).     (Saluda,  N.  C.). 
Fig.  7.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 


BULL.  MUS.  COMP.  ZOOL. 


LITHOBIIDAE.   PLATE  3 


HELIOTYPE  CO.   BOSTON 


PLATE  4. 


CHAMBERLIN. —  Lithobiid  Genera. 


PLATE  4. 


Typhlobius  coccus  (Bollman).     (Saluda,  N.  C.). 

Fig.  1.     Anterior  portion  of  prosternum. 

Fig.  2.     Claw  of  left  gonopod  of  9  ,  ventral  view. 

Paitobius  naiwatvs  '(Chamberlin).     (Landrum,  N.  C.). 

Fig.  3.    Anterior  portion  of  prosternum. 

Fig.  4.     Basal  spines  of  left  gonopod  of  9  ,  ventral  view. 


Paitobius  carolinae  (Chamberlin). 

Fig.  5.    Anterior  portion  of  prosternum. 

Fig.  6.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 


BULL.  MUS.COMP.  ZOOL. 


LITHOBIIDAE.    PLATE  4 


^r****  m&*>**?i^ 


/ 


'• 

3 


_ 

5 


A-  -A 
\, 


in 


-.. 


HELIOTYPE  CO.   BOS 


PLATE  5. 


CHAMBERLIN. —  Lithobiid  Genera. 


PLATE   6. 

Paitobius  tdbius  (Chamberlin).     (Johnson  City,  Tenn.). 
Fig.  1.     Basal  spines  of  left  gonopod  of  9 ,  view  a  little  ectad  of  ventral. 

Paitobius  zinus  (Chamberlin). 
Fig.  2.     Basal  spines  of  left  gonopod  of  9  ,  ventral  view. 

Paitobius  adelus  Chamberlin.     (Upsal,  Pa.). 
Fig.  3.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

Taiyubius  angelus  (Chamberlin).     (Santa  Barbara,  Cal.). 

Fig.  4.     Anterior  portion  of  prosternum. 
Fig.  5.     Basal  spines  of  left  gonopod  of  9  • 

Taiyubius  harrielae  (Chamberlin).     (Colorado). 
Fig.  6.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

Nadabius  oreinus  Chamberlin.     (Santa  Barbara,  Cal.). 
Fig.  7.    Anterior  portion  of  prosternum. 


BULL.  MUS.COMP.  ZOOL. 


LITHOBIIDAE.   PLATE  5 


HELIOTYPE  CO.   BOSTOfs 


PLATE  6. 


CHAMBEBLIN. —  Lithobiid  Genera. 


PLATE  6. 

Nadabius  oreinus  Chamberlin.     (Santa  Barbara,  Cal.). 
Fig.  1.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

Nadabius  mesechinus  (Chamberlin).     (Meacham,  Oregon). 
Fig.  2.     Basal  spines  of  left  gonopod  of   9 . 

Nadabius  aristeus  Chamberlin.     (Macapin,  N.  J.). 

Fig.  3.     Basal  spines  of  left  gonopod  of   9  . 
Fig.  4.    Anterior  portion  of  prosternum. 

Sonibius  parvus  Chamberlin.     (Grout's  Mill,  Vt.). 
Fig.  5.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

Tidabius  cantabrigensis  (Meinert).     (Type,  Cambridge,  Mass.). 

Fig.  6.     Anterior  portion  of  prosternum. 

Fig.  7.     Basal  spines,  right  gonopod  of  9 ,  ventral  view. 


BULL.  MUS.  COMP.  2OOL. 


LITHOBIIDAE.    PLATE  6 


HEOOTYPE  CO.   BOSTOK 


PLATE  7. 


CHAMBEBLIN. —  Lithobiid  Genera. 


PLATE  7. 

Nadabius  pullus  (Bollman). 

Fig.  1.    Anterior  portion  of  prosternum.     (Paratype,  Bloomington,  Ind.). 

Fig.  2.  Basal  spines  of  left  gonopod  of  9 ,  ventral  view.  (Paratype, 
Bloomington,  Ind.). 

Fig.  3.  Portion  of  tibia  and  first  tarsal  joint  of  anal  leg  of  cf,  mesal  aspect, 
showing  tibial  crest.  (Lynchburg,  Va.). 

Nadabius  coloradensis  (Cockerell).     (Manitou,  Col.). 
Fig.  4.     Basal  spines  of  right  gonopod  of  9 ,  ventral  view. 

Nadabius  eigenmanni  (Bollman). 
Fig.  5.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

Nadabius  iowensis  (Meinert). 
Fig.  6.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 


BULL.  MUS.  COMP.  ZOOL. 


LITHOBIIDAE.   PLATE  7 


HEilOTYPE  CO.   BOSTC 


PLATE  8. 


CHAMBERLIN. —  Lithobiid  Genera. 


PLATE  8. 

Nadabius  iowensis  (Meinert).     (Boone,  Iowa).    . 
;.  1.     Portion  of  tibia  and  tarsus  of  anal  leg  of  cf,  mesal  view,  showing 


Pokabius  bilabiatus  (Wood).     (DeWitt,  Iowa). 
Fig.  2.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

Pokabius  bilabiatus  verdescens  Chamberlin.     (Type,  East  Peoria,  111.). 

Fig.  3.     Femur  and  portion  of  the  two  contiguous  joints  of  left  anal  leg  of 
d"  showing  the  characteristic  lobes. 

Pokabius  iginus  (Chamberlin).     (Washington). 

Fig.  4.     Femur  and  portion  of  prefemur  and  tibia  of  right  anal  leg  of  d", 
dorsal  view. 


BULL.  MUS.  COMP.  ZOOL. 


LITHOBIIDAE.    PLATE 


2 


4 


HE4.IOTYPE  CO.   BOSTON 


PLATE  9. 


CHAMBERON. —  Lithobiid  Genera. 


PLATE  9. 

PokaUus  clavigerens  (Chamberlin) .     (Pacific  Grove,  Cal.). 

Fig  1.    Femur  and  part  of  prefemur  and  tibia  of  left  anal  leg  of  cT,  sub- 
dorsal  view. 

Fig.  2.    Basal  spines  of  left  gonopod  of  9  . 

Pokabiiis  disantus  Chamberlin.     (Type,  Laurel  Canyon,  Cal.). 

Fig.  3.     Femur  and  portion  of  the  two  contiguous  joints  of  the  left  anal  leg 
of  the  d\  subdorsal  view. 


Pokdbius  pitophilus  Chamberlin.     (Truckee,  Cal.). 

Fig.  4.     Femur  and  portion  of  the  two  contiguous  joints  of  the  left  anal  leg 
of  <?,  mesal  view. 

Fig.  5.     Basal  spines  of  right  gonopod  of  9 ,  ventral  view. 


' 


BULL.  MUS.  COMP.ZOOL. 


LITHOBIIDAE.   PLATE  9 


HELIOTYPE  CO.   BOSTON 


PLATE  10U 


CHAMBERLIN. —  Lithobiid  Genera. 


PLATE  10. 

Pokabius  centurio  (Chamberlin).     (Las  Valles,  N.  M.). 

Fig.  1.     Femur  and  portion  of  prefemur  and  tibia  of  anal  leg  of  cf,  view  a 
little  ectad  of  dorsal. 
Fig.  2.    Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

Pokabius  utahensis  (Chamberlin). 

Fig.  3.  Femur  and  portion  of  the  two  contiguous  joints  of  the  anal  leg  of  o", 
subdorsal  view.  (Provo  Canyon,  Utah  Co.,  Utah). 

Fig.  4.  Basal  spines  of  left  gonopod  of  9,  ventral  view  (Little  Willow 
Canyon,  Salt  Lake  Co.,  Utah). 

Pokabius  iginus  (Chamberlin).     (Paratype,  Washington). 
Fig.  5.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 


BULL.  MUS.  COMP.  ZOOL. 


LITHOBIIDAE.    PLATE  10 


, 


.    -  .         -vipiii. 


HELIOTYPE  CO.   BOSTON 


PLATE  11. 


CHAMBERLIN. —  Lithobiid  Genera. 


PLATE  11. 


Pokabius  gilae  Chamberlin.     (Thatcher,  Arizona). 

Fig.  1.  Femur  and  portion  of  prefemur  and  tibia  of  anal  leg  of  <?,  dorsal 
view. 

Pokdbim  sokovus  (Chamberlin).     (Cotype,  Las  Vegas,  Nev.). 

Fig.  2.  Femur  and  portion  of  the  two  contiguous  joints  of  anal  leg  of  d" , 
mesal  view. 

Fig.  3.     Basal  spines  of  right  gonopod  of  9 ,  ventral  view. 

Pokabius  collium  (Chamberlin). 

Fig.  4.     Anterior  portion  of  prosternum.    (Antelope  Is. ,  Gt.  Salt  Lake,  Utah) . 

Fig.  5.  Basal  spines  of  left  gonopod  of  9 .  (Antelope  Is.,  Gt.  Salt  Lake, 
Utah). 

Fig.  6.  Femur  and  portion  of  the  two  contiguous  joints  of  anal  leg  of  c" , 
dorsal  view. 


BULL.  MUS.COMP.ZOOL. 


LITHOBIIDAE.    PLATE  1 1 


\/ 


HELIOTYFE  CO.   BOSTON 


PLATE  12. 


CHAMBERLTN. —  Lithobiid  Genera. 


PLATE  12. 

Pokabius  castellopes  (Chamberlin).     (Shasta  Springs,  Cal.). 

Fig.  1.     Femur  and  portion  of  the  two  contiguous  joints  of  anal  leg  of  d", 
lateral  view. 

Pokabius  socius  (Chamberlin).     (Provo,  Utah). 
Fig.  2.    Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 

Pokabius  helenae  Chamberlin.     (Helena,  Montana). 
Fig.  3.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view.    (Helena,  Montana). 

Simobius  ginampus  (Chamberlin).     (Pullman,  Washington). 

Fig.  4.     Portion  of  fifth  and  sixth  joints  of  penult  leg  of  cf,  dorsal  view, 
showing  the  characteristic  tibial  process. 
Fig.  5.     Basal  spines  of  left  gonopod  of  9 ,  ventral  view. 


BULL.  MUS.  COMP.  ZOOL. 


LITHOBIIDAE.    PLATE  12 


5 


HELIOTYFE  CO.   BOSTON 


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